Posts Tagged ‘How to’

How to set up Notify by email expiring local UNIX user accounts on Linux / BSD with a bash script

Thursday, August 24th, 2023


If you have already configured Linux Local User Accounts Password Security policies Hardening – Set Password expiry, password quality, limit repatead access attempts, add directionary check, increase logged history command size and you want your configured local user accounts on a Linux / UNIX / BSD system to not expire before the user is reminded that it will be of his benefit to change his password on time, not to completely loose account to his account, then you might use a small script that is just checking the upcoming expiry for a predefined users and emails in an array with lslogins command like you will learn in this article.

The script below is written by a colleague Lachezar Pramatarov (Credit for the script goes to him) in order to solve this annoying expire problem, that we had all the time as me and colleagues often ended up with expired accounts and had to bother to ask for the password reset and even sometimes clearance of account locks. Hopefully this little script will help some other unix legacy admin systems to get rid of the account expire problem.

For the script to work you will need to have a properly configured SMTP (Mail server) with or without a relay to be able to send to the script predefined email addresses that will get notified. 

Here is example of a user whose account is about to expire in a couple of days and who will benefit of getting the Alert that he should hurry up to change his password until it is too late 🙂

[root@linux ~]# date
Thu Aug 24 17:28:18 CEST 2023

[root@server~]# chage -l lachezar
Last password change                                    : May 30, 2023
Password expires                                        : Aug 28, 2023
Password inactive                                       : never
Account expires                                         : never
Minimum number of days between password change          : 0
Maximum number of days between password change          : 90
Number of days of warning before password expires       : 14

Here is the that will report the user

# vim  /usr/local/bin/


# This script will send warning emails for password expiration 
# on the participants in the following list:
# 20, 15, 10 and 0-7 days before expiration
# ! Script sends expiry Alert only if day is Wednesday – if (( $(date +%u)==3 )); !

# email to send if expiring
# the users that are admins added to belong to this group
notify_email_header_customer_name='Customer Name';

declare -A mails=(
# list below accounts which will receive account expiry emails

# syntax to define uid / email
# [“account_name_from_etc_passwd”]="real_email_addr@fqdn";

#    [“abc”]=""
#    [“cba”]=""
#    [“acct7”]=""
#    [“acct8”]=""
#    [“acct9”]=""

declare -A days

while IFS="=" read -r person day ; do
done < <(lslogins –noheadings -o USER,GROUP,PWD-CHANGE,PWD-WARN,PWD-MIN,PWD-MAX,PWD-EXPIR,LAST-LOGIN,FAILED-LOGIN  –time-format=iso | awk '{print "echo "$1" "$2" "$3" $(((($(date +%s -d \""$3"+90 days\")-$(date +%s)))/86400)) "$5}' | /bin/bash | grep -E " $admin_group " | awk '{print $1 "=" $4}')

#echo ${days[laprext]}
for person in "${!mails[@]}"; do
     echo "$person ${days[$person]}";

#     echo $tmp
# each person will receive mails only if 20th days / 15th days / 10th days remaining till expiry or if less than 7 days receive alert mail every day

     if  (( (${tmp}==20) || (${tmp}==15) || (${tmp}==10) || ((${tmp}>=0) && (${tmp}<=7)) )); 
         echo "Hello, your password for $(hostname -s) will expire after ${days[$person]} days.” | mail -s “$notify_email_header_customer_name $(hostname -s) server password expiration”  -r passwd_expire ${mails[$person]};
     elif ((${tmp}<0));
#          echo "The password for $person on $(hostname -s) has EXPIRED before{days[$person]} days. Please take an action ASAP.” | mail -s “EXPIRED password of  $person on $(hostname -s)”  -r EXPIRED ${mails[$person]};

# ==3 meaning day is Wednesday the day on which OnCall Person changes

        if (( $(date +%u)==3 ));
             echo "The password for $person on $(hostname -s) has EXPIRED. Please take an action." | mail -s "EXPIRED password of  $person on $(hostname -s)"  -r EXPIRED $alert_email;


To make the script notify about expiring user accounts, place the script under some directory lets say /usr/local/bin/ and make it executable and configure a cron job that will schedule it to run every now and then.

# cat /etc/cron.d/passwd_expire_cron

# /etc/cron.d/pwd_expire
# Check password expiration for users
# 2023-01-16 LPR
02 06 * * * root /usr/local/bin/ >/dev/null

Script will execute every day morning 06:02 by the cron job and if the day is wednesday (3rd day of week) it will send warning emails for password expiration if 20, 15, 10 days are left before account expires if only 7 days are left until the password of user acct expires, the script will start sending the Alarm every single day for 7th, 6th … 0 day until pwd expires.

If you don't have an expiring accounts and you want to force a specific account to have a expire date you can do it with:

# chage -E 2023-08-30 someuser

Or set it for new created system users with:

# useradd -e 2023-08-30 username

That's it the script will notify you on User PWD expiry.

If you need to for example set a single account to expire 90 days from now (3 months) that is a kind of standard password expiry policy admins use, do it with:

# date -d "90 days" +"%Y-%m-%d"

Ideas for script improvement

The downside of the script if you have too many local user accounts is you have to hardcode into it the username and user email_address attached to and that would be tedios task if you have 100+ accounts. 

However it is pretty easy if you already have a multitude of accounts in /etc/passwd that are from UID range to loop over them in a small shell loop and build new array from it. Of course for a solution like this to work you will have to have defined as user data as GECOS with command like chfn.

[georgi@server ~]$ chfn
Changing finger information for test.
Name [test]: 
Office []:
Office Phone []: 
Home Phone []: 


[root@server test]# finger georgi
Login: georgi                       Name: georgi
Directory: /home/georgi                   Shell: /bin/bash
On since чт авг 24 17:41 (EEST) on :0 from :0 (messages off)
On since чт авг 24 17:43 (EEST) on pts/0 from :0
   2 seconds idle
On since чт авг 24 17:44 (EEST) on pts/1 from :0
   49 minutes 30 seconds idle
On since чт авг 24 18:04 (EEST) on pts/2 from :0
   32 minutes 42 seconds idle
New mail received пт окт 30 17:24 2020 (EET)
     Unread since пт окт 30 17:13 2020 (EET)
No Plan.

Then it should be relatively easy to add the GECOS for multilpe accounts if you have them predefined in a text file for each existing local user account.

Hope this script will help some sysadmin out there, many thanks to Lachezar for allowing me to share the script here.
Enjoy ! 🙂

How to monitor Postfix Mail server work correct with simple one liner Zabbix user parameter script / Simple way to capture and report SMTP machine issues Zabbix template

Thursday, June 22nd, 2023


In this article, I'm going to show you how to setup a very simple monitoring if a local running SMTP (Postfix / Qmail / Exim) is responding correctly on basic commands. The check would helpfully keep you in track to know whether your configured Linux server local MTA (Mail Transport Agent) is responding on requests on TCP / IP protocol Port 25, as well as a check for process existence of master (that is the main postfix) proccess, as well as the usual postfix spawned sub-processes qmgr (the postfix queue manager), tsl mgr (TLS session cache and PRNG manager), pickup (Postfix local mail pickup) – or email receiving process.


Normally a properly configured postfix installation on a Linux whatever you like distribution would look something like below:

#  ps -ef|grep -Ei 'master|postfix'|grep -v grep
root        1959       1  0 Jun21 ?        00:00:00 /usr/libexec/postfix/master -w
postfix     1961    1959  0 Jun21 ?        00:00:00 qmgr -l -t unix -u
postfix     4542    1959  0 Jun21 ?        00:00:00 tlsmgr -l -t unix -u
postfix  2910288    1959  0 11:28 ?        00:00:00 pickup -l -t unix -u

At times, during mail server restarts the amount of processes that are sub spawned by postfix, may very and if you a do a postfix restart

# systemctl restart postfix

The amout of spawned processes running as postfix username might decrease, and only qmgr might be available for second thus in the consequential shown Template the zabbix processes check to make sure the Postfix is properly operational on the Linux machine is made to check for the absolute minumum of 

1. master (postfix process) that runs with uid root
2. and one (postfix) username binded proccess 

If the amount of processes on the host is less than this minimum number and the netcat is unable to simulate a "half-mail" sent, the configured Postfix alarm Action (media and Email) will take place, and you will get immediately notified, that the monitored Mail server has issue!

The idea is to use a small one liner connection with netcat and half simulate a normal SMTP transaction just like you would normally do:


root@pcfrxen:/root # telnet localhost 25
Connected to localhost.
Escape character is '^]'.
220 This is Mail2 Pc-Freak.NET ESMTP
HELO localhost
250 This is Mail2 Pc-Freak.NET
250 ok


and then disconnect the connection.

1. Create new zabbix userparameter_smtp_check.conf file

The simple userparameter one liner script to do the task looks like this:

# vi /etc/zabbix/zabbix_agent.d/userparameter_smtp_check.conf

UserParameter=smtp.check,(if [[ $(echo -e “HELO localhost\n MAIL FROM: root@$HOSTNAME\n RCPT TO:\n  QUIT\n” | /usr/bin/nc localhost 25 -w 5 2>&1 | grep -Ei ‘220\s.*\sESMTP\sPostfix|250\s\.*|250\s\.*\sOk|250\s\.*\sOk|221\.*\s\w’|wc -l) == ‘5’ ]]; then echo "SMTP OK 1"; else echo "SMTP NOK 0"; fi)

Set the proper permissions so either file is owned by zabbix:zabbix or it is been able to be read from all system users.

# chmod a+r /etc/zabbix/zabbix_agent.d/userparameter_smtp_check.conf

2. Create a new Template for the Mail server monitoring


Just like any other template name it with what fits you as you see, I've call it PROD SMTP Monitoring, as the template is prepared to specifically monitor In Production Linux machines, and a separate template is used to monitor the Quality Assurance (QAs) as well as PreProd (Pre Productions).

3. Create the followng Items and Depedent Item to process zabbix-agent received data from the Userparam script

Above is the list of basic Items and Dependent Item you will need to configure inside the SMTP Check zabbix Template.

The Items should have the following content and configurations:


*Name: postfix_main_proc.service
Type: Zabbix agent(active)
*Key: proc.num[master,root]
Type of Information: Numeric (unassigned)
*Update interval: 30s
Custom Intervals: Flexible
*History storage period: 90d
*Trend storage period: 365d
Show Value: as is
Applications: Postfix Checks
Populated host inventory field: -None-
Description: The item counts master daemon process that runs Postfix daemons on demand

Where the arguments pased to proc.num[] function are:
  master is the process that is being looked up for and root is the username with which the the postfix master daemon is running. If you need to adapt it for qmail or exim that shouldn't be a big deal you only have to in advance check the exact processes that are normally running on the machine
and configure a similar process check for it.

*Name: postfix_sub_procs.service_cnt
Type: Zabbix agent(active)
*Key: proc.num[,postfix]
Type of information: Numeric (unassigned)
Update Interval: 30s
*History Storage period: Storage Period 90d
*Trend storage period: Storage Period 365d
Description: The item counts master daemon processes that runs postfix daemons on demand.

Here the idea with this Item is to check the number of processes that are running with user / groupid that is postfix. Again for other SMPT different from postfix, just set it to whatever user / group 
you would like zabbix to look up for in Linux the process list. As you can see here the check for existing postfix mta process is done every 30 seconds (for more critical environments you can put it to less).

For simple zabbix use this Dependent Item is not necessery required. But as we would like to process more closely the output of the userparameter smtp script, you have to set it up.
If you want to write graphical representation by sending data to Grafana.

*Name: postfix availability check
Key: postfix_boolean_check[boolean]
Master Item: PROD SMTP Monitoring: postfix availability check
Type of Information: Numeric unassigned
*History storage period: Storage period 90d
*Trend storage period: 365d

Applications: Postfix Checks

Description: It returns boolean value of SMTP check
1 – True (SMTP is OK)
0 – False (SMTP does not responds)

Enabled: Tick

*Name: postfix availability check
*Key: smtp.check
Custom intervals: Flexible
*Update interval: 30 m
History sotrage period: Storage Period 90d
Applications: Postfix Checks
Populates host inventory field: -None-
Description: This check is testing if the SMTP relay is reachable, without actual sending an email
Enabled: Tick

4. Configure following Zabbix Triggers


Note: The severity levels you should have previosly set in Zabbix up to your desired ones.

Name: postfix master root process is not running
*Problem Expression: {PROD SMTP Monitoring:proc.num[master,root].last()}<1

OK event generation: Recovery expression
*Recovery Expression: {PROD SMTP Monitoring:proc.num[master,root].last()}>=1
Allow manual close: Tick

Description: The item counts master daemon process that runs Postfix daemon on demand.
Enabed: Tick

I would like to have an AUTO RESOLVE for any detected mail issues, if an issue gets resolved. That is useful especially if you don't have the time to put the Zabbix monitoring in Maintainance Mode during Operating system planned updates / system reboots or unexpected system reboots due to electricity power loss to the server colocated – Data Center / Rack . 

*Name: postfix master sub processes are not running
*Problem Expression: {P09 PROD SMTP Monitoring:proc.num[,postfix].last()}<1
PROBLEM event generation mode: Single
OK event closes: All problems

*Recovery Expression: {P09 PROD SMTP Monitoring:proc.num[,postfix].last()}>=1
Problem event generation mode: Single
OK event closes: All problems
Allow manual close: Tick
Enabled: Tick

Name: SMTP connectivity check
Severity: WARNING
*Expression: {PROD SMTP Monitoring:postfix_boolen_check[boolean].last()}=0
OK event generation: Expression
PROBLEM even generation mode: SIngle
OK event closes: All problems

Allow manual close: Tick
Enabled: Tick

5. Configure respective Zabbix Action



As the service is tagged with 'pci service' tag we define the respective conditions and according to your preferences, add as many conditions as you need for the Zabbix Action to take place.

Assuming that communication chain beween Zabbix Server -> Zabbix Proxy (if zabbix proxy is used) -> Zabbix Agent works correctly you should start receiving that from the userparameter script in Zabbix with the configured smtp.check userparam key every 30 minutes.

Note that this simple nc check will keep a trail records inside your /var/log/maillog for each netcat connection, so keep in mind that in /var/log/maillog on each host which has configured the SMTP Check zabbix template, you will have some records  similar to:

# tail -n 50 /var/log/maillog
2023-06-22T09:32:18.164128+02:00 lpgblu01f postfix/smtpd[2690485]: improper command pipelining after HELO from localhost[]:  MAIL FROM:\n RCPT TO:\n  QUIT\n
2023-06-22T09:32:18.208888+02:00 lpgblu01f postfix/smtpd[2690485]: 32EB02005B: client=localhost[]
2023-06-22T09:32:18.209142+02:00 lpgblu01f postfix/smtpd[2690485]: disconnect from localhost[] helo=1 mail=1 rcpt=1 quit=1 commands=4
2023-06-22T10:02:18.889440+02:00 lpgblu01f postfix/smtpd[2747269]: connect from localhost[]
2023-06-22T10:02:18.889553+02:00 lpgblu01f postfix/smtpd[2747269]: improper command pipelining after HELO from localhost[]:  MAIL FROM:\n RCPT TO:\n  QUIT\n
2023-06-22T10:02:18.933933+02:00 lpgblu01f postfix/smtpd[2747269]: E3ED42005B: client=localhost[]
2023-06-22T10:02:18.934227+02:00 lpgblu01f postfix/smtpd[2747269]: disconnect from localhost[] helo=1 mail=1 rcpt=1 quit=1 commands=4
2023-06-22T10:32:26.143282+02:00 lpgblu01f postfix/smtpd[2804195]: connect from localhost[]
2023-06-22T10:32:26.143439+02:00 lpgblu01f postfix/smtpd[2804195]: improper command pipelining after HELO from localhost[]:  MAIL FROM:\n RCPT TO:\n  QUIT\n
2023-06-22T10:32:26.186681+02:00 lpgblu01f postfix/smtpd[2804195]: 2D7F72005B: client=localhost[]
2023-06-22T10:32:26.186958+02:00 lpgblu01f postfix/smtpd[2804195]: disconnect from localhost[] helo=1 mail=1 rcpt=1 quit=1 commands=4
2023-06-22T11:02:26.924039+02:00 lpgblu01f postfix/smtpd[2860398]: connect from localhost[]
2023-06-22T11:02:26.924160+02:00 lpgblu01f postfix/smtpd[2860398]: improper command pipelining after HELO from localhost[]:  MAIL FROM:\n RCPT TO:\n  QUIT\n
2023-06-22T11:02:26.963014+02:00 lpgblu01f postfix/smtpd[2860398]: EB08C2005B: client=localhost[]
2023-06-22T11:02:26.963257+02:00 lpgblu01f postfix/smtpd[2860398]: disconnect from localhost[] helo=1 mail=1 rcpt=1 quit=1 commands=4
2023-06-22T11:32:29.145553+02:00 lpgblu01f postfix/smtpd[2916905]: connect from localhost[]
2023-06-22T11:32:29.145664+02:00 lpgblu01f postfix/smtpd[2916905]: improper command pipelining after HELO from localhost[]:  MAIL FROM:\n RCPT TO:\n  QUIT\n
2023-06-22T11:32:29.184539+02:00 lpgblu01f postfix/smtpd[2916905]: 2CF7D2005B: client=localhost[]
2023-06-22T11:32:29.184729+02:00 lpgblu01f postfix/smtpd[2916905]: disconnect from localhost[] helo=1 mail=1 rcpt=1 quit=1 commands=4



That's all folks use the :
Configuration -> Host (menu)

and assign the new SMTP check template to as many of the Linux hosts where you have setup the Userparameter script and Enjoy the new mail server monitoring at hand.

How to log multiple haproxy / apache / mysql instance via haproxy log-tagging / Segregating log management for multiple HAProxy instances using rsyslog

Tuesday, May 23rd, 2023




This article provides a guide on refining haproxy  logging mechanism by leveraging the `programname` property in rsyslog, coupled with the `log-tag` directive in haproxy.
This approach will create a granular logging setup, separating logs according to their originating services and specific custom tags, enhancing overall log readability.

Though the article is written concretely for logging multiple log streams from haproxy this can be successfully applied
for any other Linux service to log as many concrete log-tagged data streams as you prefer.


The guide focuses on tailoring the logging mechanisms for two haproxy  instances named `haproxy` and `haproxyssl`, utilizing the `programname` property in rsyslog and the `log-tag` directive in haproxy for precise log management.

The haproxy and haproxyssl instances are two separate systemd config file prepared instances.
haproxy instance is simple haproxy proxying tcp traffic in non-encrypted form, whether haproxyssl is a special instance
prepared to tunnel the incoming http traffic in ssl form. Both instances of haproxy runs as a separate processes on the server.

Here is the systemd configuration of haproxy systemd service file:

# cat /usr/lib/systemd/system/haproxy.service
Description=HAProxy Load Balancer

Environment="CONFIG=/etc/haproxy/haproxy.cfg" "PIDFILE=/run/"
ExecStartPre=/usr/sbin/haproxy -f $CONFIG -c -q $OPTIONS
ExecStart=/usr/sbin/haproxy -Ws -f $CONFIG -p $PIDFILE $OPTIONS
ExecReload=/usr/sbin/haproxy -f $CONFIG -c -q $OPTIONS
ExecReload=/bin/kill -USR2 $MAINPID


As well as the systemd service configuration for haproxyssl:

# cat /usr/lib/systemd/system/haproxyssl.service
Description=HAProxy Load Balancer

Environment="CONFIG=/etc/haproxy/haproxy_ssl_prod.cfg" "PIDFILE=/run/"
ExecStartPre=/usr/sbin/haproxyssl -f $CONFIG -c -q $OPTIONS
ExecStart=/usr/sbin/haproxyssl -Ws -f $CONFIG -p $PIDFILE $OPTIONS
ExecReload=/usr/sbin/haproxyssl -f $CONFIG -c -q $OPTIONS
ExecReload=/bin/kill -USR2 $MAINPID



Step 1: Configuring HAProxy instances with `log-tag`

To distinguish between logs from two HAProxy instances, `log-tag` directive is used to add tags to logs. This tag is used to filter these logs in rsyslog.
Modify the HAProxy configuration file in `/etc/haproxy/haproxy.*.cfg`

HAProxy Instance 1 (haproxy)

# Global settings
      log local6 debug
      log-tag      haproxy

HAProxy Instance 2 (haproxyssl)

# Global settings
    log local5 debug
    log-tag      haproxyssl


Step 2: Implementing rsyslog configuration for haproxy logs

Next, create a new rsyslog configuration file, stored in /etc/rsyslog.d/. Ensure the new configuration file ends in `.conf`

HAProxy Instance 1 (haproxy)

Now add rsyslog rules to filters logs based on the `programname` and the custom log tag:

# vi /etc/rsyslog.d/55_haproxy.conf
if $programname == 'haproxy' then /var/log/haproxy.log

HAProxy Instance 2 (haproxyssl)
# vi /etc/rsyslog.d/51_haproxy_ssl.conf
if $programname == 'haproxy_ssl' then /var/log/haproxy_ssl.log

These rules filter logs that originate from haproxy  and contain the respective string haproxy   or haproxy_ssl , directing them to their respective log files. The `& stop` directive ensures that rsyslog stops processing the log once a match is found, preventing dublication.

Finally, restart both the haproxy and rsyslog services for the changes to take effect:

# systemctl restart haproxy
# systemctl restart haproxyssl
# systemctl restart rsyslog

Reading References

haproxy:   log-tag directive

rsyslog:    rsyslogd documentation

This is a guest article originally written by: Dimitar Paskalev, guest blogging with good interesting articles is always mostly welcome 

How to log every Linux executed command by every running system program to separte log via rsyslog for better server Security and audit trails

Wednesday, March 15th, 2023


To keep a good eye on installed Debian Linux server security if you have to be PCI compliant (e.g. follow a high security) standards or you work in a company, where system security is crucial and any kind of security breach is untorrelated and in case of unexpected security holes exploited on running system processess listening on network peripherals (that malicious crackers) does to be able to easily identify what really happened e.g. do a Security RCA (Root Cause Analysis) for how this hack happened in order to mitigate it for future if possible capture the crackers and close the security hole the better, some kind of paranoid running program logging is required.

For such higher security systems, Linux / BSD / UNIX sysadmins can benefit from;

Snoopy command logger – a small library that logs all program executions on your Linux/BSD system.

Embedding snoopy into a running uptodate system is relatively easy, you either have to download the respective distribution package (in this particular article that would be Debian GNU / Linux) or for Linux distributions, that doesn't have the package integrated into the existing package repositories or externally available package repos, the code can be easily git cloned and installed from github snoopy program page following the

However consider that snoopy run and logging the executed commands, make sure that if you use it you have rsyslogd configured to log to external logging server to make sure (someone did not manipulate the running system to avoid their actions being logged by snoopy, this is pointed by snoopy security disclaimer on the FAQ of official github snoopy project page, the page reads as so:

Security disclaimer
WARNING: Snoopy is not a reliable auditing solution.
Rogue users can easily manipulate environment to avoid their actions being logged by Snoopy. Consult this FAQ entry for more information.                

Most likely this warning is pointed out by the tool authors, in order to set the logging Tool creators free for any liability in case if someone uses the snoopy tool for some unauthorized logging
and sniffing of systems etc.

Before we proceed with the tool, install first for some clarity it is a good idea to know on what kind of Debian Linux you're about to install Snoopy command logger.

root@linux:~ # cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"
NAME="Debian GNU/Linux"
VERSION="11 (bullseye)"

1. Prepare separate log file for snoopy that will keep log of every system command run by running processes visible by (ps -ef)

Next check the permissions user / group and read / write / executable flags with which the default generated rsyslog will be writting and set snoopy to whatever you would like it to write with

root@linux:~ # cat /etc/rsyslog.conf | grep "^\$File\|\$Umask"~
$FileOwner root
$FileGroup adm
$FileCreateMode 0640

Create Rsyslog configuration for snoopy.log

root@linux:~ # cat << EOF | sudo tee /etc/rsyslog.d/01-snoopy.conf
# Send snoopy messages to a dedicated logfile
if (\$programname startswith "snoopy") then {
  action(type="omfile" fileOwner="root" fileGroup="root" fileCreateMode="0600" file="/var/log/snoopy.log")


To make sure that snoopy library will be preloaded after installation on next boot:

root@linux:~ # cat << EOF | sudo debconf-set-selections
snoopy snoopy/install-ld-preload boolean true


root@linux:~ # systemctl restart rsyslog


root@linux:~ # systemctl status rsyslog
● rsyslog.service – System Logging Service
     Loaded: loaded (/lib/systemd/system/rsyslog.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2023-03-14 12:59:05 EET; 59min ago
TriggeredBy: ● syslog.socket
       Docs: man:rsyslogd(8)
   Main PID: 713745 (rsyslogd)
      Tasks: 6 (limit: 4654)
     Memory: 1.1M
        CPU: 548ms
     CGroup: /system.slice/rsyslog.service
             └─713745 /usr/sbin/rsyslogd -n -iNONE

мар 14 12:59:05 haproxy2 systemd[1]: Started System Logging Service.
мар 14 12:59:05 haproxy2 rsyslogd[713745]: warning: ~ action is deprecated, consider using the 'stop' statement instead [v8.210>
мар 14 12:59:05 haproxy2 rsyslogd[713745]: [198B blob data]
мар 14 12:59:05 haproxy2 rsyslogd[713745]: [198B blob data]
мар 14 12:59:05 haproxy2 rsyslogd[713745]: [198B blob data]
мар 14 12:59:05 haproxy2 rsyslogd[713745]: [198B blob data]
мар 14 12:59:05 haproxy2 rsyslogd[713745]: imuxsock: Acquired UNIX socket '/run/systemd/journal/syslog' (fd 3) from systemd.  [>
мар 14 12:59:05 haproxy2 rsyslogd[713745]: [origin software="rsyslogd" swVersion="8.2102.0" x-pid="713745" x-info="https://www.>
мар 14 13:19:05 haproxy2 rsyslogd[713745]: — MARK —
мар 14 13:39:05 haproxy2 rsyslogd[713745]: — MARK —

2. Install snoopy deb package and configure it

root@linux:~ # apt install snoopy
Четене на списъците с пакети… Готово
Изграждане на дървото със зависимости… Готово
Четене на информацията за състоянието… Готово
Следните пакети са били инсталирани автоматично и вече не са необходими:
  bsdmainutils cpp-8 geoip-database libasan5 libbind9-161 libcroco3 libdns1104 libdns1110 libevent-core-2.1-6
  libevent-pthreads-2.1-6 libgdk-pixbuf-xlib-2.0-0 libgdk-pixbuf2.0-0 libgeoip1 libicu63 libisc1100 libisc1105 libisccc161
  libisccfg163 libisl19 liblwres161 libmpdec2 libmpx2 libperl5.28 libpython2-stdlib libpython2.7-minimal libpython2.7-stdlib
  libpython3.7-minimal libpython3.7-stdlib libreadline7 netcat-traditional node-ansi-align node-arrify node-bluebird
  node-boxen node-builtin-modules node-call-limit node-camelcase node-cli-boxes node-cliui node-co node-concat-stream
  node-config-chain node-cross-spawn node-cyclist node-decamelize node-decompress-response node-deep-extend node-detect-indent
  node-detect-newline node-duplexer3 node-duplexify node-editor node-end-of-stream node-errno node-execa node-find-up
  node-flush-write-stream node-from2 node-fs-vacuum node-get-caller-file node-get-stream node-got node-has-symbol-support-x
  node-has-to-string-tag-x node-import-lazy node-invert-kv node-is-buffer node-is-builtin-module node-is-npm node-is-object
  node-is-plain-obj node-is-retry-allowed node-is-stream node-isurl node-json-buffer node-kind-of node-latest-version
  node-lazy-property node-lcid node-libnpx node-locate-path node-lowercase-keys node-mem node-merge-stream node-mimic-fn
  node-mimic-response node-minimist node-mississippi node-node-uuid node-npm-run-path node-os-locale node-p-cancelable
  node-p-finally node-p-limit node-p-locate node-p-timeout node-package-json node-parallel-transform node-path-exists
  node-path-is-inside node-prepend-http node-proto-list node-prr node-pump node-pumpify node-qw node-rc
  node-registry-auth-token node-registry-url node-require-directory node-require-main-filename node-semver-diff node-sha
  node-shebang-command node-shebang-regex node-slide node-sorted-object node-stream-each node-stream-iterate node-stream-shift
  node-strip-eof node-strip-json-comments node-term-size node-through2 node-timed-out node-typedarray node-uid-number
  node-unpipe node-url-parse-lax node-url-to-options node-which-module node-widest-line node-wrap-ansi node-xdg-basedir
  node-xtend node-y18n node-yargs node-yargs-parser perl-modules-5.28 python-pkg-resources python2 python2-minimal python2.7
  python2.7-minimal python3.7-minimal

Използвайте „apt autoremove“ за да ги премахнете.
Следните НОВИ пакети ще бъдат инсталирани:
0 актуализирани, 1 нови инсталирани, 0 за премахване и 1 без промяна.
Необходимо е да се изтеглят 46,0 kB архиви.
След тази операция ще бъде използвано 124 kB допълнително дисково пространство.
Изт:1 bullseye/main amd64 snoopy amd64 2.4.12-1 [46,0 kB]
Изтеглени 46,0 kB за 0с (93,2 kB/сек)
Предварително настройване на пакети …

Selecting previously unselected package snoopy.
(Reading database … 56067 files and directories currently installed.)
Preparing to unpack …/snoopy_2.4.12-1_amd64.deb ...
Unpacking snoopy (2.4.12-1) …
Setting up snoopy (2.4.12-1) …
Processing triggers for libc-bin (2.31-13+deb11u5) …

root@linux:/etc# ls -al /var/log/snoopy.log
-rw——- 1 root root 14472 14 мар 13:40 /var/log/snoopy.log

Any specific configuration for snoopy can be tuned through /etc/snoopy.ini

Now you will find all the commands executed by all monitored running processes in /var/log/snoopy.

root@linux:/etc# tail -30 /var/log/snoopy.log
Mar 14 12:59:32 haproxy2 snoopy[713804]: [login:root ssh:( 62796 22) sid:713792 tty:/dev/pts/2 (0/root) uid:root(0)/root(0) cwd:/]: ldconfig
Mar 14 12:59:32 haproxy2 snoopy[713806]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: who
Mar 14 12:59:32 haproxy2 snoopy[713807]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: wc -l
Mar 14 13:00:07 haproxy2 snoopy[713815]: [login:root ssh:((undefined)) sid:713815 tty:(none) ((none)/(none)) uid:root(0)/root(0) cwd:/usr/lib/sysstat]: /usr/lib/sysstat/sadc -F -L -S DISK 1 1 /var/log/sysstat
Mar 14 13:00:32 haproxy2 snoopy[713823]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: who
Mar 14 13:00:32 haproxy2 snoopy[713824]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: wc -l
Mar 14 13:01:32 haproxy2 snoopy[713834]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: who
Mar 14 13:01:32 haproxy2 snoopy[713835]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: wc -l
Mar 14 13:02:32 haproxy2 snoopy[713843]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: who
Mar 14 13:02:32 haproxy2 snoopy[713844]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: wc -l
Mar 14 13:03:32 haproxy2 snoopy[713855]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: who
Mar 14 13:03:32 haproxy2 snoopy[713856]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: wc -l
Mar 14 13:04:32 haproxy2 snoopy[713868]: [login:zabbix ssh:((undefined)) sid:682168 tty:(none) ((none)/(none)) uid:zabbix(108)/zabbix(108) cwd:/]: who

3. Set up logrotation (archiving) for snoopy logs

root@linux:/etc# vim /etc/logrotate.d/snoopy    

/var/log/snoopy.log {
        rotate 30
        create 640 root adm


If you want to test logrotation without actually rotating the file:               

root@linux:/etc# logrotate –debug –force /etc/logrotate.d/snoopy   
  log needs rotating
rotating log /var/log/snoopy.log, log->rotateCount is 30
dateext suffix '-20230314'
glob pattern '-[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]'
previous log /var/log/snoopy.log.1 does not exist
renaming /var/log/snoopy.log.30.gz to /var/log/snoopy.log.31.gz (rotatecount 30, logstart 1, i 30),

renaming /var/log/snoopy.log.1.gz to /var/log/snoopy.log.2.gz (rotatecount 30, logstart 1, i 1),
renaming /var/log/snoopy.log.0.gz to /var/log/snoopy.log.1.gz (rotatecount 30, logstart 1, i 0),
log /var/log/snoopy.log.31.gz doesn't exist — won't try to dispose of it
renaming /var/log/snoopy.log to /var/log/snoopy.log.1
creating new /var/log/snoopy.log mode = 0640 uid = 0 gid = 4

4. Monitoring only selected applications  executed commands with snoopy                                                                             

By default snoopy after installed will set itself to monitor all kind of running processes on the system is done by preloading the ldconfig's (

root@haproxy2:/etc# cat /etc/

If you want to monitor a concrete application and not log everything from the running processes in process list, comment this out this line run ldconfig command

Then to any concrete application you would like to monitor with snoopy add to its init script either /etc/init.d/app_init_script or to systemctl's start script before the application binary program run:

export LD_PRELOAD=/lib/

  As per the README states

 Snoopy is placed in /etc/ to trap all occurrences of exec, if 
 you wish to monitor only certain applications you can do so through the    
 LD_PRELOAD environment variable.
Simply set it to /lib/ before  loading the application.

For example

 # export LD_PRELOAD=/lib/                                           
 # lynx                           


How to install and configure AIDE ( Advanced Intrusion Detection Environment ) on Debian GNU / Linux 11 to monitor files for changes

Thursday, March 9th, 2023


How to install and configure AIDE ( Advanced Intrusion Detection Environment ) on Debian GNU / Linux 11 to monitor files for changes

Having a intrusion detection system is essential to keeping a server security to good level and being compliant with PCI (Payment Card Industry) DSS Standards. It is a great thing for the sake to protect oneself from hackers assaults. 

There is plenty of Intrusion Detection systems available all around since many years, in the past one of main ones for Linux as older system administrators should remember was Tripwire – integrity tool for monitoring and alerting on specific file change(s) on a range of systems

Tripwire is still used today but many today prefer to use AIDE that is a free software replacement for Tripwire under GPL (General Public License), that is starting to become like a "standard"  for many Unix-like systems as an inexpensive baseline control and rootkit detection system.

In this article I'll explain shortly how to Install / Configure and Use AIDE to monitor, changes with files on the system.

But before proceeding it is worthy to mention on some of the alternatives companies and businesses choose to as an IDS (Intrusion Detection Systems), that is useful to give a brief idea of the sysadmins that has to deal with Security, on what is some of the main Intrusion Detection Systems adopted on UNIX OSes today:

  • Samhain

    An integrity checker and host intrusion detection system that can be used on single hosts as well as large, UNIX-based networks. It supports central monitoring as well as powerful (and new) stealth features to run undetected in memory, using steganography. Samhain is an open-source multiplatform application for POSIX systems (Unix, Linux, Cygwin/Windows).

  • OSSEC 
    OSSEC uses a centralized, cross-platform architecture allowing multiple systems to be monitored and managed.
  • Snort
    IDS which has the capabilities to prevent attacks. By taking a particular action based on traffic patterns, it can become an intrusion prevention system (IPS). – written in Pure C.
  • Zeek (Bro)
    Zeek helps to perform security monitoring by looking into the network's activity. It can find suspicious data streams. Based on the data, it alert, react, and integrate with other tools – written in C++.
  • Maltrail (Maltrail monitors for traffic on the network that might indicate system compromise or other bad behavior. It is great for intrusion detection and monitoring. – written in Python).

1. Install aide deb package

# apt -y install aide

root@haproxy2:~# aide -v
Aide 0.17.3

Compiled with the following options:


Default config values:
config file: <none>
database_in: <none>
database_out: <none>

Available hashsum groups:
md5: yes
sha1: yes
sha256: yes
sha512: yes
rmd160: yes
tiger: yes
crc32: yes
crc32b: yes
haval: yes
whirlpool: yes
gost: yes
stribog256: no
stribog512: no

Default compound groups:
R: l+p+u+g+s+c+m+i+n+md5+acl+selinux+xattrs+ftype+e2fsattrs+caps
L: l+p+u+g+i+n+acl+selinux+xattrs+ftype+e2fsattrs+caps
>: l+p+u+g+i+n+acl+S+selinux+xattrs+ftype+e2fsattrs+caps
H: md5+sha1+rmd160+tiger+crc32+haval+gost+crc32b+sha256+sha512+whirlpool
X: acl+selinux+xattrs+e2fsattrs+caps

2. Prepare AIDE configuration and geenrate (initialize) database

Either you can use the default AIDE configuration which already has a preset rules for various files and directories to be monitored,
or you might add up additional ones.

  • For details on configuration of aide.conf accepted options "man aide.conf"

The rules and other configurations resides lays under  /etc/aide/ directory

The AIDE database is located under /var/lib/aide

root@server:~# ls -al /var/lib/aide/
общо 33008
drwxr-xr-x  2 root root     4096  9 мар 12:38 ./
drwxr-xr-x 27 root root     4096  9 мар 12:01 ../
-rw——-  1 root root 16895467  9 мар 16:03 aide.db
-rw——-  1 root root 16895467  9 мар 18:49

Also, details about major setting rules config regarding how AIDE will run via cronjob as with most debian services are into /etc/default/aide

Default aide.conf config is in /etc/aide/aide.conf if you need custom stuff to do with it simply edit it.

Here is an Example:
Lets say you want to omit some directory to not be monitored by aide, which would otherwise do, i.e.
omit /var/log/* from monitoring

# At the end of file /etc/aide/aide.conf



  • Initialize the aide database first time

Run aideinit command, aideinit will create a new baseline database –  /var/lib/aide/ (a baseline)
Note that, /var/lib/aide/aide.db is the old database that aide uses to check against for any changes of files / directories on the configured monitored filesystem objects.

root@server:~# aideinit
Running aide –init…

debug1: client_input_channel_req: channel 0 rtype reply 1
debug1: client_input_channel_req: channel 0 rtype reply 1
debug1: client_input_channel_req: channel 0 rtype reply 1
debug1: client_input_channel_req: channel 0 rtype reply 1
debug1: client_input_channel_req: channel 0 rtype reply 1
Start timestamp: 2023-03-09 12:06:16 +0200 (AIDE 0.17.3)
AIDE initialized database at /var/lib/aide/

Number of entries:      66971

The attributes of the (uncompressed) database(s):

 SHA256    : nVrYljiBFM/KaKCTjbaJtR2w6N8vc8qN
 SHA512    : S1ZNB0DCqb4UTmuqaalTgiQ3UAltTOzO
 RMD160    : xaUnfW1+/DJV/6FEm/nn1k1UKOU=
 TIGER     : nGYEbX281tsQ6T21VPx1Hr/FwBdwF4cK
 CRC32     : fzf7cg==
 HAVAL     : yYQw/87KUmRiRLSu5JcEIvBUVfsW/G9H
 WHIRLPOOL : 6b5y42axPjpUxWFipUs1PtbgP2q0KJWK
 GOST      : sHAzx7hkr5H3q8TCSGCKjndEiZgcvCEL

End timestamp: 2023-03-09 12:38:30 +0200 (run time: 32m 14s)

Be patient now, go grab a coffee / tea or snack as the command might take up to few minutes for the aide to walk through the whole monitored filesystems and built its database.

root@server:~# echo cp /var/lib/aide/aide.db{.new,}
cp /var/lib/aide/ /var/lib/aide/aide.db


root@server:~# cp /var/lib/aide/aide.db{.new,}

root@server:~# aide –check –config /etc/aide/aide.conf

Start timestamp: 2023-03-09 13:01:32 +0200 (AIDE 0.17.3)
AIDE found differences between database and filesystem!!

  Total number of entries:      66972
  Added entries:                1
  Removed entries:              0
  Changed entries:              7

Added entries:

f+++++++++++++++++: /var/lib/aide/aide.db

Changed entries:

d =…. mc.. .. . : /etc/aide
d =…. mc.. .. . : /root
f <…. mci.H.. . : /root/.viminfo
f =…. mc..H.. . : /var/lib/fail2ban/fail2ban.sqlite3
d =…. mc.. .. . : /var/lib/vnstat
f =…. mc..H.. . : /var/lib/vnstat/vnstat.db
f >b… mc..H.. . : /var/log/sysstat/sa09

Detailed information about changes:

Directory: /etc/aide
 Mtime     : 2023-03-09 12:04:03 +0200        | 2023-03-09 12:51:11 +0200
 Ctime     : 2023-03-09 12:04:03 +0200        | 2023-03-09 12:51:11 +0200

Directory: /root
 Mtime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 12:51:11 +0200
 Ctime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 12:51:11 +0200

File: /root/.viminfo
 Size      : 18688                            | 17764
 Mtime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 12:51:11 +0200
 Ctime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 12:51:11 +0200
 Inode     : 133828                           | 133827
 SHA256    : aV54gi33aA/z/FuBj2ZioU2cTa9H16TT | dnFdLVQ/kx3UlTah09IgEMrJ/aYgczHe
             TzkLSxBDSB4=                     | DdxDAmPOSAM=

3. Test aide detects file changes

Create a new file and append some text and rerun the aide check


root@server:~# touch /root/test.txt
root@server:~# echo aaa > /root/test.txt
root@server:~# aide –check –config /etc/aide/aide.conf


Start timestamp: 2023-03-09 13:07:21 +0200 (AIDE 0.17.3)
AIDE found differences between database and filesystem!!

  Total number of entries:      66973
  Added entries:                2
  Removed entries:              0
  Changed entries:              7

Added entries:

f+++++++++++++++++: /root/test.txt
f+++++++++++++++++: /var/lib/aide/aide.db

Changed entries:

d =…. mc.. .. . : /etc/aide
d =…. mc.. .. . : /root
f <…. mci.H.. . : /root/.viminfo
f =…. mc..H.. . : /var/lib/fail2ban/fail2ban.sqlite3
d =…. mc.. .. . : /var/lib/vnstat
f =…. mc..H.. . : /var/lib/vnstat/vnstat.db
f >b… mc..H.. . : /var/log/sysstat/sa09


The same command can be shortened for the lazy typist:

root@server:~# aide -c /etc/aide/aide.conf -C

The command will basically try to check the deviation between the AIDE database and the filesystem.

4. Limiting AIDES Integrity Checks to Specific Files / Directories

In order to limit the integrity checks to a specific entries for example /etc, pass the –limit REGEX option to AIDE check command where REGEX is the entry to check.

For example, check and update the database entries matching /etc, you would run aide command as shown below;

root@server:~# aide -c /etc/aide/aide.conf –limit /etc –check


AIDE found differences between database and filesystem!!
Limit: /etc

  Total number of entries:      66791
  Added entries:                0
  Removed entries:              0
  Changed entries:              2

Changed entries:

d =…. mc.. .. . : /etc/aide
d =…. mc.. .. . : /etc/default

Detailed information about changes:

Directory: /etc/aide
 Mtime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 16:43:03 +0200
 Ctime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 16:43:03 +0200

Directory: /etc/default
 Mtime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 18:42:12 +0200
 Ctime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 18:42:12 +0200

The attributes of the (uncompressed) database(s):

 SHA256    : sjCxyIkr0nC/gTkNmn7DNqAQWttreDF6
 SHA512    : vNMpb54qxrbOk6S1Z+m9r0UwGvRarkWY
 RMD160    : anhm5E6UlKmPYYJ4WYnWXk/LT3A=
 TIGER     : 5e1wycoF35/ABrRf7FNypZ45169VTuV4
 CRC32     : EAJlFg==
 HAVAL     : R5imONWRYgNGEfhBTc096K+ABnMFkMmh
 GOST      : F5zO2Ovtvf+f7Lw0Ef++ign1znZAQMHM

End timestamp: 2023-03-09 20:02:18 +0200 (run time: 1m 32s)

5. Add the modified /root/test.txt to AIDE list of known modified files database

root@server:~# aide –update –config /etc/aide/aide.
  ERROR: cannot open config file '/etc/aide/aide.': No such file or directory


root@server:~# ​ aide –update –config /etc/aide/aide.conf

Start timestamp: 2023-03-09 18:45:17 +0200 (AIDE 0.17.3)
AIDE found differences between database and filesystem!!
New AIDE database written to /var/lib/aide/

  Total number of entries:      66791
  Added entries:                0
  Removed entries:              0
  Changed entries:              8

Changed entries:

d =…. mc.. .. . : /etc/aide
d =…. mc.. .. . : /etc/default
d =…. mc.. .. . : /root
f >…. mci.H.. . : /root/.viminfo
f >…. mci.H.. . : /root/test.txt
f =…. mc..H.. . : /var/lib/fail2ban/fail2ban.sqlite3
d =…. mc.. .. . : /var/lib/vnstat
f =…. mc..H.. . : /var/lib/vnstat/vnstat.db

Detailed information about changes:

Directory: /etc/aide
 Mtime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 16:43:03 +0200
 Ctime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 16:43:03 +0200

Directory: /etc/default
 Mtime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 18:42:12 +0200
 Ctime     : 2023-03-09 12:06:13 +0200        | 2023-03-09 18:42:12 +0200

Directory: /root
 Mtime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 18:44:34 +0200
 Ctime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 18:44:34 +0200

File: /root/.viminfo
 Size      : 16706                            | 16933
 Mtime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 18:44:34 +0200
 Ctime     : 2023-03-09 15:59:53 +0200        | 2023-03-09 18:44:34 +0200
 Inode     : 136749                           | 133828
 SHA256    : KMHGoMVJo10BtafVrWIOLt3Ht9gK8bc+ | rrp8S3VftzZzvjBP1JC+PBpODv9wPKGw
             9uHh/z7iJWA=                     | TA+hyhTiY+U=
 SHA512    : ieDHy7ObSTfYm5d8DtYcHKxHya13CS65 | PDAJjyZ39uU3kKFo2lHBduTqxMDq4i01
             ObMYIRAre6IgvLslEs0ZodQFyrczMyRt | 1Kvm/h6xzFhHtFgjidtcemG8wDcjtfNF
             +d6SrW0gn3skKn2B7G09eQ==         | Z7LO230fgGeO7UepqtxZjQ==
 RMD160    : nUgg/G4zsVGKzVmmrqltuYUDvtg=     | jj61KAFONK92mj+u66RDJmxFhmI=
 TIGER     : 3vPSOrla5k+k2br1E2ES4eNiSZ2novFX | mn4kNCzd8SQr2ID2VSe4f4l0ta7pO/xo
 CRC32     : NDnMgw==                         | AyzVUQ==
 HAVAL     : Q9/KozxRiPbLEkaIfnBUZdEWftaF52Mw | 6jADKV6jg7ZVr/A/oMhR4NXc8TO1AOGW
             7tiR7DXhl0o=                     | NrYe+j6UcO0=
 WHIRLPOOL : vB/ZMCul4hN0aYd39gBu+HmZT/peRUI8 | mg6c1lYYVNZcy4mVzGojwraim8e3X2/R
             KDkaslNb8+YleoFWx0mbhAbkGurc0+jh | urVvEmbsgTuUCJOuf9+OrEACiF0fbe/x
             YPBviZIKcxUbTc2nGthTWw==         | t+BXnSQWk08OL9EI6gMGqA==
 GOST      : owVGTgU9BH3b0If569wQygw3FAbZIZde | ffx29GV2jaCB7XzuNjdiRzziIiZYnbi3
             eAfQfzlRPGY=                     | Ar7jyNMUutk=

File: /root/test.txt
 Size      : 4                                | 8
 Mtime     : 2023-03-09 13:07:12 +0200        | 2023-03-09 18:44:34 +0200
 Ctime     : 2023-03-09 13:07:12 +0200        | 2023-03-09 18:44:34 +0200
 Inode     : 133828                           | 136751
 SHA256    : F+aC8GC1+OR+oExcSFWQiwpa1hICImD+ | jUIZMGfiMdAlWFHu8mmmlml4qAGNQNL5
             UOEeywzAq3Y=                     | 6NhzJ1sYFZE=
 SHA512    : d+UmFKFBzvGadt5hk+nIRbjP//7PSXNl | ixn20lcEMDEtsJo3hO90Ea/wHWLCHcrz
             Pl16XRIUUPq2FCiQ4PeUcVciukJX7ijL | seBWunbBysY0z3BWcfgnN2vH05WfRfvA
             D045ZvGOEcnmL6a6vwp0jw==         | QiNtQS1tStuEdB3Voq54zQ==
 RMD160    : I6waxKN3rMx4WTz4VCUQXoNoxUg=     | urTh1j1t3UHchnJGnBG4lUZnjI4=
 TIGER     : cwUYgfKHcJnWXcA0pr/OKuxuoxh+b9lA | prstKqCfMXL39aVGFPA0kX4Q9x7a+hUn
 CRC32     : UD78Dw==                         | zoYiEA==
 HAVAL     : bdbKR9LvPgsYClViKiHx48fFixfIL/jA | ZdpdeMhw4MvKBgWsM4EeyUgerO86Rt82
             F3tjdc2Gm8Y=                     | W94fJFRWbrM=
 WHIRLPOOL : OLP0Y4oKcqW2yEvme8z419N1KE4TB9GJ | Xk8Ujo3IU2SzSqbJFegq7p1ockmrnxJF
             biHn/9XgrBz4fQiDJ8eHpx+0exA9hXmY | R3Rfstd1jWSwLFNTEwfbRRw+TARtRK50
             EbbakMJJdzLt1ipKWiV9gg==         | iWJeHLsD5dZ+CzV0tf4sUg==
 GOST      : ystISzoeH/ZznYrrXmxe4rwmybWMpGuE | GhMWNxg7Is0svJ+5LP+DVWbgt+CDQO+3
             0PzRnVEqnR8=                     | 08dwBuVAwB8=

File: /var/lib/fail2ban/fail2ban.sqlite3
 Mtime     : 2023-03-09 15:55:01 +0200        | 2023-03-09 18:45:01 +0200
 Ctime     : 2023-03-09 15:55:01 +0200        | 2023-03-09 18:45:01 +0200
 SHA256    : lLilXNleqSgHIP1y4o7c+oG5XyUPGzgi | NCJJ2H6xgCw/NYys1LMA7hOWwoOoxI8Y
             RHYH+zvlAL4=                     | 4SJygfqEioE=
 SHA512    : iQj2pNT4NES4fBcujzdlEEGZhDnkhKgc | ClQZ5HMOSayUNb//++eZc813fiMJcXnj
             QDlGFSAn6vi+RXesFCjCABT7/00eEm5/ | vTGs/2tANojoe6cqpsT/LaJ3QZXpmrfh
             ILcaqlQtBSLJgHjMQehzdg==         | syVak1I4n9yg8cDKEkZUvw==
 RMD160    : Xg4YU8YI935L+DLvkRsDanS4DGo=     | SYrQ27n+/1fvIZ7v+Sar/wQHulI=
 TIGER     : 2WhhPq9kuyeNJkOicDTDeOeJB8HR8zZe | o1LDZtRclri2KfZBe5J3D4YhM05UaP4E
 CRC32     : NQmi4A==                         | tzIsqg==
 HAVAL     : t1ET+84+8WgfwqlLy4R1Qk9qGZQRUbJI | MwVnjtM3dad/RuN2BfgsySX2DpfYq4qi
             z2J0ROGduXc=                     | H1pq6RYsA6o=
 WHIRLPOOL : xKSn71gFIVhk5rWJIBaYQASl0V+pGn+3 | m5LEXfhBbhWFg/d8CFJhklOurmRSkDSG
             N85R0tiCKsTZ2+LRkxDrzcVQdss2k8+z | LC/vICnbEWzLwrCuMwBi1/e5wDNIY8gK
             oqExhoXtPsMaREjpCugd3Q==         | mvGn40x+G4cCYNZ6lGT9Zg==
 GOST      : WptpUlfooIlUjzDHU8XGuOU2waRud5SR | i6K4COXU0nyZ1mL3ZBuGUPz/ZXTj8KKQ
             E/tnoBqk+q0=                     | L6VNyS8/X2Y=

Directory: /var/lib/vnstat
 Mtime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 18:45:01 +0200
 Ctime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 18:45:01 +0200

File: /var/lib/vnstat/vnstat.db
 Mtime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 18:45:00 +0200
 Ctime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 18:45:00 +0200
 SHA256    : X/lnJuuSo4jX4HRzxMBodnKHAjQFvugi | oqtY3HTNds/qDNFCRAEsfN5SuO0U5LRg
             2sh2c0u69x8=                     | otc5z1y+eGY=
 SHA512    : U/g8O6G8cuhsqCUCbrElxgiy+naJKPkI | y+sw4LX8mlDWkRJMX38TsYSo1DQzxPOS
             hG7vdH9rBINjakL87UWajT0s6WSy0pvt | 068otnzw2FSSlM5X5j5EtyJiY6Hd5P+A
             ALaTcDFKHBAmmFrl8df2nQ==         | jFiWStMbx+dQidXYZ4XFAw==
 RMD160    : F6YEjIIQu2J3ru7IaTvSemA9e34=     | bmVSaRKN2qU7qpEWkzfXFoH4ZK4=
 TIGER     : UEwLoeR6Qlf2oOI58pUCEDaWk0pHDkcY | 0Qb4nUqe3cKh/g5CQUnOXGfjZwJHjeWa
 CRC32     : Bv3/6A==                         | jvW6mg==
 HAVAL     : VD7tjHb8o8KTUo5xUH7eJEmTWgB9zjft | rumfiWJvy/sTK/09uj7XlmV3f7vj6KBM
             kOkzKxFWqqU=                     | qeOuKvu0Zjc=
 WHIRLPOOL : wR0qt8u4N8aQn8VQ+bmfrxB7CyCWVwHi | FVWDRE3uY6qHxLlJQLU9i9QggLW+neMj
             ADHpMTUxBEKOpOBlHTWXIk13qYZiD+o/ | Wt+Dj9Rz92BG9EomgLUgUkxfiVFO8cMq
             XtzTB4rMbxS4Z5PAdC/07A==         | WaR/KKq3Z7R8f/50tc9GMQ==
 GOST      : l3ibqMkHMSPpQ+9ok51/xBthET9+JQMd | qn0GyyCg67KRGP13At52tnviZfZDgyAm
             OZtiFGYXmgU=                     | c82NXSzeyV0=

The attributes of the (uncompressed) database(s):

 SHA256    : sjCxyIkr0nC/gTkNmn7DNqAQWttreDF6
 SHA512    : vNMpb54qxrbOk6S1Z+m9r0UwGvRarkWY
 RMD160    : anhm5E6UlKmPYYJ4WYnWXk/LT3A=
 TIGER     : 5e1wycoF35/ABrRf7FNypZ45169VTuV4
 CRC32     : EAJlFg==
 HAVAL     : R5imONWRYgNGEfhBTc096K+ABnMFkMmh
 GOST      : F5zO2Ovtvf+f7Lw0Ef++ign1znZAQMHM

 SHA256    : QRwubXnz8md/08n28Ek6DOsSQKGkLvuc
 SHA512    : 238RmI1PHhd9pXhzcHqM4+VjNzR0es+3
 RMD160    : GJWuX/nIPY05gz62YXxk4tWiH5I=
 TIGER     : l0aOjXlM4/HjyN9bhgBOvvCYeqoQyjpw
 CRC32     : KFz6GA==
 HAVAL     : a//4jwVxF22URf2BRNA612WOOvOrScy7
 WHIRLPOOL : MBf+NeXElUvscJ2khIuAp+NDu1dm4h1f
 GOST      : EQnPh6jQLVUqaAK9B4/U4V89tanTI55N

End timestamp: 2023-03-09 18:49:51 +0200 (run time: 4m 34s)

6. Substitute old aide database with the new that includes the modified files

As you see AIDE detected the changes in /root/test.txt

To apply the changes be known by AIDE for next time (e.g. this file was authorized and supposed to be written there) simply move the new generated database
to current aide database.

# copy generated DB to master DB
root@dlp:~# cp -p /var/lib/aide/ /var/lib/aide/aide.db

7. Check once again to make sure recently modified files are no longer seen as changed by AIDE

Recheck again the database to make sure the files you wanted to omit are no longer mentioned as changed

root@server:~# aide –check –config /etc/aide/aide.conf
Start timestamp: 2023-03-09 16:23:05 +0200 (AIDE 0.17.3)
AIDE found differences between database and filesystem!!

  Total number of entries:      66791
  Added entries:                0
  Removed entries:              0
  Changed entries:              3

Changed entries:

f =…. mc..H.. . : /var/lib/fail2ban/fail2ban.sqlite3
d =…. mc.. .. . : /var/lib/vnstat
f =…. mc..H.. . : /var/lib/vnstat/vnstat.db

Detailed information about changes:

File: /var/lib/fail2ban/fail2ban.sqlite3
 Mtime     : 2023-03-09 15:55:01 +0200        | 2023-03-09 16:25:02 +0200
 Ctime     : 2023-03-09 15:55:01 +0200        | 2023-03-09 16:25:02 +0200
 SHA256    : lLilXNleqSgHIP1y4o7c+oG5XyUPGzgi | MnWXC2rBMf7DNJ91kXtHXpM2c2xxF60X
             RHYH+zvlAL4=                     | DfLUQLHiSiY=
 SHA512    : iQj2pNT4NES4fBcujzdlEEGZhDnkhKgc | gxHVBxhGTKi0TjRE8/sn6/gtWsRw7Mfy
             QDlGFSAn6vi+RXesFCjCABT7/00eEm5/ | /wCfPlDK0dkRZEbr8IE2BNUhBgwwocCq
             ILcaqlQtBSLJgHjMQehzdg==         | zuazTy4N4x6X8bwOzRmY0w==
 RMD160    : Xg4YU8YI935L+DLvkRsDanS4DGo=     | +ksl9kjDoSU9aL4tR7FFFOK3mqw=
 TIGER     : 2WhhPq9kuyeNJkOicDTDeOeJB8HR8zZe | 9cvXZNbU+cp5dA5PLiX6sGncXd1Ff5QO
 CRC32     : NQmi4A==                         | y6Oixg==
 HAVAL     : t1ET+84+8WgfwqlLy4R1Qk9qGZQRUbJI | aPnCrHfmZAUm7QjROGEl6rd3776wO+Ep
             z2J0ROGduXc=                     | s/TQn7tH1tY=
 WHIRLPOOL : xKSn71gFIVhk5rWJIBaYQASl0V+pGn+3 | 9Hu6NBhz+puja7uandb21Nt6cEW6zEpm
             N85R0tiCKsTZ2+LRkxDrzcVQdss2k8+z | bTsq4xYA09ekhDHMQJHj2WpKpzZbA+t0
             oqExhoXtPsMaREjpCugd3Q==         | cttMDX8J8M/UadqfL8KZkQ==
 GOST      : WptpUlfooIlUjzDHU8XGuOU2waRud5SR | WUQfAMtye4wADUepBvblvgO+vBodS0Ej
             E/tnoBqk+q0=                     | cIbXy4vpPYc=

Directory: /var/lib/vnstat
 Mtime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 16:25:01 +0200
 Ctime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 16:25:01 +0200

File: /var/lib/vnstat/vnstat.db
 Mtime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 16:25:01 +0200
 Ctime     : 2023-03-09 16:00:00 +0200        | 2023-03-09 16:25:01 +0200
 SHA256    : X/lnJuuSo4jX4HRzxMBodnKHAjQFvugi | N1lzhV3+tkDBud3AVlmIpDkU1c3Rqhnt
             2sh2c0u69x8=                     | YqE8naDicoM=
 SHA512    : U/g8O6G8cuhsqCUCbrElxgiy+naJKPkI | +8B9HvHhOp1C/XdlOORjyd3J2RtTbRBF
             hG7vdH9rBINjakL87UWajT0s6WSy0pvt | b0Moo2Gj+cIxaMCu5wOkgreMp6FloqJR
             ALaTcDFKHBAmmFrl8df2nQ==         | UH4cNES/bAWtonmbj4W7Vw==
 RMD160    : F6YEjIIQu2J3ru7IaTvSemA9e34=     | 8M6TIOHt0NWgR5Mo47DxU28cp+4=
 TIGER     : UEwLoeR6Qlf2oOI58pUCEDaWk0pHDkcY | Du9Ue0JA2URO2tiij31B/+663OaWKefR
 CRC32     : Bv3/6A==                         | v0Ai4w==
 HAVAL     : VD7tjHb8o8KTUo5xUH7eJEmTWgB9zjft | XA+vRnMNdVGFrO+IZtEA0icunWqBGaCf
             kOkzKxFWqqU=                     | leR27LN4ejc=
 WHIRLPOOL : wR0qt8u4N8aQn8VQ+bmfrxB7CyCWVwHi | HG31dNEEcak2zZGR24W7FDJx8mh24MaJ
             ADHpMTUxBEKOpOBlHTWXIk13qYZiD+o/ | BQNhqkuS6R/bmlhx+P+eQ/JimwPAPOaM
             XtzTB4rMbxS4Z5PAdC/07A==         | xWG7cMETIXdT9sUOUal8Sw==
 GOST      : l3ibqMkHMSPpQ+9ok51/xBthET9+JQMd | y6Ek/TyAMGV5egkfCu92Y4qqk1Xge8c0
             OZtiFGYXmgU=                     | 3ONXRveOlr0=

The attributes of the (uncompressed) database(s):

 SHA256    : sjCxyIkr0nC/gTkNmn7DNqAQWttreDF6
 SHA512    : vNMpb54qxrbOk6S1Z+m9r0UwGvRarkWY
 RMD160    : anhm5E6UlKmPYYJ4WYnWXk/LT3A=
 TIGER     : 5e1wycoF35/ABrRf7FNypZ45169VTuV4
 CRC32     : EAJlFg==
 HAVAL     : R5imONWRYgNGEfhBTc096K+ABnMFkMmh
 GOST      : F5zO2Ovtvf+f7Lw0Ef++ign1znZAQMHM

End timestamp: 2023-03-09 16:27:33 +0200 (run time: 4m 28s)

As you can see there are no new added entries for /root/test.txt and some other changed records for vnstat service as well as fail2ban ones, so the Intrusion detection system works just as we expected it.

8. Configure Email AIDE changed files alerting Email recipient address

From here on aide package has set its own cron job which is automatically doing the check operation every day and any new file modifications will be captured and alerts sent to local root@localhost mailbox account, so you can check it out later with mail command.

If you want to sent the Email alert for any files modifications occured to another email, assuming that you have a locally running SMTP server with a mail relay to send to external mails, you can do it via /etc/default/aide via:


For example change it to a FQDN email address

9.Force AIDE to run AIDE at specitic more frequent time intervals

You can as well install a cron job to execute AIDE at specific time intervals, as of your choice

Lets say you want to run a custom prepared set of files to monitor in /etc/aide/aide_custom_config.conf configure a new cronjob like below:

root@server:~# crontab -u root -e
*/5 * * * * aide -c /etc/aide/aide_custom_config.conf -u && cp /var/lib/custom-aide/aide.db{.new,}

This will execute AIDE system check every 5 minutse and email the report to ealier configured email via /etc/default/aide

10. Check the output of AIDE for changes – useful for getting a files changes from aide from scripts

Check the command exit status.

root@server:~# echo $?

According to AIDE man pages, the AIDE’s exit status is normally 0 if no errors occurred. Except when the –check, –compare or –update command was requested, in which case the exit status is defined as:

   1 * (new files detected?)     +

   2 * (removed files detected?) +

   4 * (changed files detected?)

   Since  those three cases can occur together, the respective error codes are added. For example, if there are new files and removed files detected, the exit status will be 1 + 2 = 3.

   Additionally, the following exit codes are defined for generic error conditions in aide help manual:

   14 Error writing error

   15 Invalid argument error

   16 Unimplemented function error

   17 Invalid configureline error

   18 IO error

   19 Version mismatch error


  • That AIDE checks might be resource intensive
    and could cause a peak in CPU use and have a negative effect on lets very loaded application server machines,
    thus causing a performance issuea during integrity checks !
  • If you are scanning file system wide and you do it frequent, be sure to provide “enough” resources or schedule the scan at a times that the Linux host will be less used !
  • Whenever you made any AIDE configuration changes, remember to initialize the database to create a baseline !

Improve MobaXterm Best Windows terminal client with some additional settings tune ups / Install extra Linux Cygwin tools on MobaXterm and various post install configuration goodies

Friday, January 20th, 2023


Earlier I've written a an article MobaXTerm: A good gnome-terminal like tabbed SSH client for Windows / Windows Putty Tabs Alternative in which I've introduced the best in my opinion SSH / Telnet / VNC / RDP / Xserver in one Terminal client emulator for Windows operating systems.

The client has been around for quite some time and it has been improving rapidly over the last 10 years, where it now more looks like a separate Operating System than a single terminal client. It's size is quite compact as well and my opinion and every self respectiving developer, system administrator, IT geek or a hacker would definitely
use the mobaxterm at home or at work place on a daily. I guess some of my readers, who have already migrated SuperPutty / SecureCRT or Putty / XMing or whatever kind of exotic Remote SSH Console terminal is used could validate this 🙂

Therefore as I've set up Mobaxterm on a multiple computers all around, I've found it useful to write a small article with some post-install hints (tune ups) one can do immediately once he has installed the Desktop or Portable Apps version of mobaxterm on desktop PC / notebook.

1. Set up your bashrc server / command aliases

Lets say you need to setup some rules for connectivity via a socks proxy to dig holes over a harsh company firewalls or add
custom options to every ssh client attempt to remote server, or simply alias some of your servers with custom connectivity options
and so on simply open vi / vim text editor from mobaxterm local terminal and place inside your rules, for example that could be anything like:


alias ssh='ssh -o stricthostkeychecking=no -o passwordauthentication=yes -o PreferredAuthentications=password  -v'
alias sftp='sftp -o stricthostkeychecking=no -o passwordauthentication=yes -o PreferredAuthentications=password'

alias work-server='ssh UserName@work-server -v -o passwordauthentication=yes -o PreferredAuthentications=password'

alias proxy='ssh -D 3128 UserName@proxyIP-host1 -o ConnectTimeout=80'
alias proxy1='ssh -D 3128 UserName@proxy-host2 -p 443 -o ConnectTimeout=60'
alias proxy3='ssh -D 3128 Username@proxy-host3 -p 443 -o ConnectTimeout=60'

Simply open the terminal and setup whatever you require
export ftp_proxy="http://proxy-host:8080"
export https_proxy="https://proxy-host:8080"
export http_proxy="http://proxy-host:8080"
export HTTP_PROXY="http://proxy-host:8080"
export HTTPS_PROXY="http://proxy-host:8080"


2. Set mobaxterm presistent directory / persistent root directory and default text editor

Make sure you have properly defined at least Persistent directory / Persistent directory if you want to keep the files under your /home/mobaxterm and root directory be able to save your data from local mobaxterm terminal work you have done.

To do so o to Configuration -> General


3. Change default settings for Opening / Closing Terminal tabs just like in gnome-terminal

MobaXterm is really awesome as the developer, followed pretty much the logic of some common GNU / Linux Terminal clients like Gnome-Terminal and KDE's default Konsole terminal.

One of the first things to do once Mobaxterm is installed on the PC is to set up nice key binds as default onces might be heard to learn at the beginning or you might have already the habit to use the certain set of key combinations on your Linux desktop:

Common once are:

1. Open tab / Close tab common once I bind to are (CTRL + T / CTRL + W)
2. Previous tab move / Next tab move keys common one I use are (ALT + LEFT / ALT + RIGHT)
3. Find in terminal (CTRL + F)


4. Make MobaXterm to automatically open a terminal to not Start local terminal every time

By default mobaxterm it is really annoying cause every time you run it after system reboot you have to select
Start local terminal
Once you run the terminal you get this prompt and you have to press on Start local terminal


How to make Mobaxterm automatically open local Terminal Tab on every boot?

To fix this so every time a local terminal is spawn on MobaXterm you have get to:

Settings -> Configuration -> Misc

Open the Following tab at startup by default it will be

<Home (Pinned)>

Change it to:



That's it on next login your Local Terminal with /bin/bash.exe will auto load !

[hipo.WINDOWS-PC] ➤ env|grep -i SHELL

5. Make menu buttons to appear smaller

Go to menu and select
View -> (Small Buttons)


6. Disable auto start of XServer to prevent a port listener on the machine on TCP port

By default mobaxterm opens XServer listener, so you can immediately connect from a remote SSH servers missing Xserver and install software requiring an XServer, for example software such as Oracle Database or some MiddleWare WebLogig or IBM's Web Sphere. This is useful but if you want to have a good security only allow this server on a purpose. Otherwise the XServer will run in parallel with rest of your Moba and just load up your PC and eat up some RAM memory. To disable it go to:


7. Change the mobaxterm Default theme to Dark

This is optional I like to set the Theme to Dark, also as a Theme for Windows as well as for MobaxTerm, the aim of that is simply to not put extra stress on my eye sight. Being on the PC around 8 to 10 hours and spending some 6 to 8 hours on console work is enough. If you want to do as well.


8. Install additional set of common Linux tools to mobaxterm to use on Windows

Tools such as:

1. Midnight Commander (mc)
2. Wget
3. Curl
4. Vim
5. Screen
6. Rsync
7. Perl
8. W3m
9. dosunix
10. unix2dos
11. gnupg
12. diffutils
13. mysql
14. mpg123
15. whois

If you want to have a set of packages pre-installed that are including above as well as the rest of mine, here is a dump of my installed mobapt manager packages:

For more simply use the experimental Mobaxterm  Graphical Package installer

[hipo.WINDOWS-PC] ➤  for i in $(cat Downloads/installed-packages-mobaxterm.txt ); do apt-cyg install $i; done

Found package GeoIP-database

Installing GeoIP-database
Downloading GeoIP-database-20180505-1.tar.xz…
Unpacking GeoIP-database-20180505-1.tar.xz…

Running postinstall scripts
Package GeoIP-database installed.

Rebasing new libraries

Found package adwaita-icon-theme

Installing adwaita-icon-theme
Downloading adwaita-icon-theme-3.26.1-1.tar.xz…

You will be prompted for a single Yes for the respository

MobApt Packages Manager


Though it is said it is experimental, I have to say the MobApt Apt Manager works quite good, I never had any issues with it so far.

9. Mobaxterm.ini the settings storage file that can help you move your configurations

If you have to prepeare new MobaXterm on multiple PCs frequently perhaps it is best to just copy the Mobaxterm.ini file. 
Here is an example of my mobaxterm.ini for download.

10. Change terminal colors and curor type and enable blinking (customizations)

Settings -> Configuration -> Terminal -> (Default Terminal Color Settings)


11. Use very useful moba Tools

For sysadmins Moba has plenty of other jems such as:

  • Network Port scanner such as Nmap with GUI

  • list open network ports (GUI interface to netmap)

  • SSH tunnel tool

  • Moba Diff

  • Wake on Lan

  • Network Packet capturer (such as tcpdump)

  • List running processes (such as taskmgr in simple form)

  • List machine hardware devices (such as Windows Device manager)

12. Remote monitoring of opened ssh session

To enable remote monitoring for a Saved session simply use the "Remote monitoring" button on the down left corner of the terminal.


Or to enable it for a new host, open:

1. "Saved sessions"
2. Click over "User sessions"
3. New Session -> (SSH)
4. Basic SSH Settings (Remote host) -> OK
5. Click over the new created session
6. Click on Remote monitoring for the opened session


13. Play some mobaxterm console games

As you might have pissed off of configuring go on and enjoy some of the great console games, some of which are also present on a normal Linux new distribution installation. 🙂


List of Moba Games

TeamWalk (Use your mouse or keyboard to connect every server to the central router)


Ctris Console tetris from Mobaxterm


Text console Solitaire from Moba


Here is NinVaders (Text Version of Space Invaders Arcade Classic)

Enjoy ! 🙂

How to dump and restore Zabbix database to do monitoring database snapshot, PostGreSQL continuous archiving Point in time recovery setup

Monday, November 21st, 2022


If you have set up a Zabbix server that is using as a database storage postgresql at home or company, then you will need to make sure you don’t loose any data by producing regular postgresql backups. This small article will show how to do the db backup in conventional way with pg_dump / pg_restore as well as how to set the continuous archiving point in time recovery end point recovery so called PITR..

1. Connect to the database and some postgres very basics

-bash-4.2$ psql DBNAME USERNAME
-bash-4.2$ psql zabbix zabbix

After you access a PostgreSQL database, you can run SQL queries and more. Here are some common psql commands:
•    To view help for psql commands, type \?.
•    To view help for SQL commands, type \h.
•    To view information about the current database connection, type \conninfo.
•    To list the database's tables and their respective owners, type \dt.
•    To list all of the tables, views, and sequences in the database, type \z.
•    To exit the psql program, type \q.

       Fundamental backup approaches with postgres

As with everything that contains valuable data, PostgreSQL databases should be backed up regularly. While the procedure is essentially simple, it is important to have a clear understanding of the underlying techniques and assumptions.
There are three fundamentally different approaches to backing up PostgreSQL data:
•    SQL dump
•    File system level backup
•    Continuous archiving

Each has its own strengths and weaknesses; each is discussed in turn in the following sections.

2.    Creating SQL Dump of postgresql target database

2.1 Manual SQL dump (custom dump format)

Use pg_dump's custom dump format. If PostgreSQL was built on a system with the zlib compression library installed, the custom dump format will compress data as it writes it to the output file.
This will produce dump file sizes similar to using gzip, but it has the added advantage that tables can be restored selectively.
The following command dumps a database using the custom dump format:

# sudo su – postgres
-bash-4.2% cd  /var/lib/pgsql/9.5/backups/
-bash-4.2$  pg_dump -Fc zabbix > /var/lib/pgsql/9.5/backups/zabbixdbdump`date "+%d%m%y%H%M%S"`.gz

2.2 Schedule backups with cron job

To automate the job schedule a cron job to do the work, somethjing like below:

# Minute   Hour   Day of Month       Month          Day of Week        Command
# (0-59)  (0-23)     (1-31)    (1-12 or Jan-Dec)  (0-6 or Sun-Sat)

@daily  pg_dump -Fc zabbix > /var/lib/pgsql/9.5/backups/Zabbix_db_dump`date "+\%d\%m\%y\%H\%M\%S"`.gz

3. Restore a database from the dump file

3.1. Restoring a database using pg_restore (usually used)

A custom-format dump is not a script for psql, but instead must be restored with pg_restore, for example:

# pg_restore -d zabbix /var/lib/pgsql/9.5/backups/Zabbix_db_dump281118151005.gz

3.2. Second Option restoing with psql after creating a restore database

# su postgres

-bash-4.2$ psql template1

-bash-4.2$ psql zabbix < /var/lib/pgsql/9.5/backups/zabbixdbdump291117151002.gz

NOTE: if you get a permission denied error when trying to restore, check the Unix permissions on the backup file and all the parent directories.

4.    Continuous Archiving and Point-in-Time Recovery (PITR) backups

At all times, PostgreSQL maintains a write ahead log (WAL) in the pg_xlog/ subdirectory of the cluster's data directory. The log records every change made to the database's data files. This log exists primarily for crash-safety purposes: if the system crashes, the database can be restored to consistency by "replaying" the log entries made since the last checkpoint. However, the existence of the log makes it possible to use a third strategy for backing up databases: we can combine a file-system-level backup with backup of the WAL files. If recovery is needed, we restore the file system backup and then replay from the backed-up WAL files to bring the system to a current state. This approach is more complex to administer than either of the previous approaches, but it has some significant benefits:

           Setting Up the WAL Archiving

In an abstract sense, a running PostgreSQL system produces an indefinitely long sequence of WAL records. The system physically divides this sequence into WAL segment files, which are normally 16MB a piece (although the segment size can be altered when building PostgreSQL). The segment files are given numeric names that reflect their position in the abstract WAL sequence. When not using WAL archiving, the system normally creates just a few segment files and then "recycles" them by renaming no-longer-needed segment files to higher segment numbers. It's assumed that segment files whose contents precede the checkpoint-before-last are no longer of interest and can be recycled.
When archiving WAL data, we need to capture the contents of each segment file once it is filled, and save that data somewhere before the segment file is recycled for reuse.
Depending on the application and the available hardware, there could be many different ways of "saving the data somewhere": we could copy the segment files to an NFS-mounted directory on another machine, write them onto a tape drive (ensuring that you have a way of identifying the original name of each file), or batch them together and burn them onto CDs, or something else entirely. To provide the database administrator with flexibility, PostgreSQL tries not to make any assumptions about how the archiving will be done. Instead, PostgreSQL lets the administrator specify a shell command to be executed to copy a completed segment file to wherever it needs to go. The command could be as simple as a cp, or it could invoke a complex shell script — it's all up to you.
To enable WAL archiving, set the wal_level configuration parameter to archive or higher, archive_mode to on, and specify the shell command to use in the archive_command configuration parameter.

In practice these settings will always be placed in the postgresql.conf e.g. (/etc/postgresql/12/main/postgresql.conf) file.

In archive_command, %p is replaced by the path name of the file to archive, while %f is replaced by only the file name. (The path name is relative to the current working directory, i.e., the cluster's data directory.)

Use %% if you need to embed an actual % character in the command.

The simplest useful command to enable PITR would, be something like:

# – Archiving config setction
archive_mode = on                    # enables archiving; off, on, or always
# (change requires restart)
archive_command = '/bin/xz -2 -z < %p > /var/lib/pgsql/9.5/archivedir/%f'               # command to use to archive a logfile segment
archive_timeout = 1h            # force a logfile segment switch after this
                                                   # number of seconds; 0 disables

How to check if network ethernet cards are active on Linux server / detect the physical connected state of a network cable / connector?

Tuesday, November 1st, 2022


Lets say you are administrating some Linux server and need to upgrade a switch and temporary move out traffic for ethernet interfaces connected via a Gigabit network to a Gigabit Cisco / Junper EX Series / HPE Aruba or Arista Platform network switch to a newer version of a switch or software.

Usually if you don't have control over the Network switch (if you're employeed in a large corporation), that migration will be handled by a colleague from the Network team in a prescheduled time slot and usually in a coordinated meeting, once the cabling is being physically moved by someone a person in the Computer Room (in DC) in the respective data center.

Then once the correct commands are executed on the network switch to remap the new cable to point to the right location on the Linux server, where the old switch was and the setup has to be double verified by the network team mate.

Once this is done either by a colleague or if you're in a smaller company and you work as one man army sysadmin and you have done it yourself.
Next step is to verify that the Ethernet LAN cards on the Linux server lets say 6 or 8 LAN cards are still connected and active to the preset Active LAN / VLANs.

On Linux this is pretty simple and there is many ways to do it with external tools like ethtool, if you're lucky and your server doesn't have to have a paranoid security rules to follow or have to be a minimilastic machine with a 100% PCI High security standards compliancy.

To check connectivity for all your ethernet interfaces you can simply run a one liner shell script like so:

[root@linux-server ~]# for i in $(ip a s|grep -i :|grep -v link|awk '{ print $2 }'|sed -e 's#:##g'|grep -v lo); do ethtool $i; done
Settings for eth0:
        Link detected: yes
Settings for eth1:
        Link detected: yes
Settings for eth2:
        Link detected: yes

So far so good but what if your RHEL / CentOS / Debian server doesn't have ethtool installed and you're not allowed to install it then how can you check whether network cable connector is indicating a network activity to the connected Ethernet LAN cards?

[root@linux-server ~]# for f in $(ls -1 /sys/class/net/); do echo "Eth inface: $f"; cat /sys/class/net/$f/operstate; done
Eth inface: eth0
Eth inface: eth1
Eth inface: eth2
Eth inface: lo

If your operstate returns something different like state unknown, e.g.:

root@linux-server ~]# cd /sys/class/net/
[root@linux-server net]# grep "" eth2/operstate
[root@linux-server net]#

[root@linux-server net]# grep "" eth{0,1,2,3}/operstate  

Then you need to check the carrier file

[root@linux-server net]# grep "" eth{0,1,2,3}/carrier

It could return either 0 or 1

The number 1 in the above output means that the network cable is physically connected to your network card’s slot meaning your network switch migration is success.

Method 2: Next, we will test a second network interface eth1:

[root@linux-server net]# cat /sys/class/net/eth1/carrier
[root@linux-server net]# cat: /sys/class/net/eth1/carrier: Invalid argument

This command’s output most likely means the the eth1 network interface is in powered down state.

So what have learned?

We have learned how to monitor the state of the network cable connected to a Linux ethernet device via external switch that is migrated without the use of any external tools like ethtool.