Posts Tagged ‘Stopping’

Install simscan on Qmail for better Mail server performance and get around unexisting suid perl in newer Linux Debian / Ubuntu servers

Tuesday, August 18th, 2015

qmail-fixing-clamdscan-errors-and-qq-errors-qmail-binary-migration-few-things-to-check-outclamav_logo-installing-clamav-antivirus-to-scan-periodically-debian-server-websites-for-viruses

I've been stuck with qmail-scanner-queue for a while on each and every new Qmail Mail server installation, I've done, this time it was not different but as time evolves and Qmail and Qmail Scanner Wrapper are not regularly updated it is getting, harder and harder to make a fully functional Qmail on newer Linux server distribution releases.

I know many would argue QMAIL is already obsolete but still I have plenty of old servers running QMAIL whose migration might cause more troubles than just continuing to use QMAIL. Moreover QMAIL once set-upped works like a charm.

I've been recently experiencing severe issues with clamdscan errors and I tried to work around this with compiling and using a suid wrapper, however still the clamdscan errors continued and as qmail-scanner is not actively developed and it is much slower than simscan, I've finally decided to give simscan as a mean to fix the clamdscan errors and thanksfully this worked as a solution.

Here is what I did "rawly" to make simscan work on this install:
 

Make sure simscan is properly installed on Debian Linux 7 or Ubuntu servers and probably (should work) on other Deb based Linuxes by following below steps:
 

a) Configure simscan with following compile time options as root (superuser)

./configure \
–enable-user=qscand \
–enable-clamav \
–enable-clamdscan=/usr/local/bin/clamdscan \
–enable-custom-smtp-reject=y \
–enable-per-domain=y \
–enable-attach=y \
–enable-dropmsg=n \
–enable-spam=y \
–enable-spam-hits=5 \
–enable-spam-passthru=y \
–enable-qmail-queue=/var/qmail/bin/qmail-queue \
–enable-ripmime=/usr/local/bin/ripmime \
–enable-sigtool-path=/usr/local/bin/sigtool \
–enable-received=y


b) Compile it

 

 make && make install-strip

c) Fix any wrong permissions of simscan queue directory

 

chmod g+s /var/qmail/simscan/

chown -R qscand:qscand /var/qmail/simscan/
chmod -R 777 simscan/chown -R qscand:qscand simscan/
chown -R qscand:qscand simscan/

d) Add some additional simscan options (how simscan is how to perform scans)

The restart qmail to make mailserver start using simscan instead of qmail-scanner, run below command (again as root):

echo ":clam=yes,spam=yes,spam_hits=8.5,attach=.vbs:.lnk:.scr:.wsh:.hta:.pif" > /var/qmail/control/simcontrol

 

e) Run /var/qmail/bin/simscanmk in order to convert /var/qmail/control/simcontrol into the /var/qmail/control/simcontrol.cdb database

/var/qmail/bin/simscanmk
/var/qmail/bin/simscanmk -g

f) Modify /service/qmail-smtpd/run to set simscan to be default Antivirus Wrapper Scanner

vim /service/qmail-smtpd/run

I'm using thibs's run script so I've uncommented the line there:

QMAILQUEUE="$VQ/bin/simscan"

Below two lines should stay commented as qmail-scanner is no longer used:

##QMAILQUEUE="$VQ/bin/qmail-scanner-queue"
##QMAILQUEUE="$VQ/bin/qmail-scanner-queue.pl"
export QMAILQUEUE

qmailctl restart
* Stopping qmail-smtpdssl.
* Stopping qmail-smtpd.
* Sending qmail-send SIGTERM and restarting.
* Restarting qmail-smtpd.
* Restarting qmail-smtpdssl.

g) Test whether simscan is properly sending / receiving emails:

echo "Testing Email" >> /tmp/mailtest.txt
env QMAILQUEUE=/var/qmail/bin/simscan SIMSCAN_DEBUG=3 /var/qmail/bin/qmail-inject hipo@my-mailserver.com < /tmp/mailtest.txt

Besides that as I'm using qscand:qscand as a user for my overall Qmail Thibs install I had to also do:

chown -R qscand:qscand /var/qmail/simscan/
chmod -R 777 simscan/
chown -R qscand:qscand simscan/

 

It might be a good idea to also place that lines in /etc/rc.local to auto change permissions on Linux boot, just in case something wents wrong with permissions.

Yeah, I know 777 is unsecure but without this permissions, I was still getting errors, plus the server doesn't have any accounts except the administrator, so I do not worry other system users might sniff on email 🙂

h) Test whether Qmail mail server send / receives fine with simscan

After that I've used another mail server with mail command to test whether mail is received:
 

mail -s "testing email1234" hipo@new-configured-qmail-server.com
asdfadsf
.
Cc:

Then it is necessery to also install latest clamav daemon from source in my case that's on Debian GNU / Linux 7, because somehow the Debian shipped binary version of clamav 0.98.5+dfsg-0+deb7u2 does fail to scan any incoming or outgoing email with error:
 

clamdscan: corrupt or unknown clamd scanner error or memory/resource/perms problem – exit status -1/72057594037927935

So to fix it you will have to install clamav on Debian Linux from source.


Voilla, that's all finally it worked !

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How to fix “sslserver: fatal: unable to load certificate” Qmail error on GNU / Linux

Friday, October 14th, 2011

After setupping a brand new Qmail installation following the QmailRocks Thibs Qmail Debian install guide , I’ve come across unexpected re-occuring error message in /var/log/qmail/qmail-smtpdssl/ , here is the message:

@400000004e9807b10d8bdb7c command-line: exec sslserver -e -vR -l my-mailserver-domain.com -c 30 -u 89 -g 89
-x /etc/tcp.smtp.cdb 0 465 rblsmtpd -r zen.spamhaus.org -r dnsbl.njabl.org -r dnsbl.sorbs.net -r bl.spamcop.net qmail-smtpd
my-mailserver-domain.com /home/vpopmail/bin/vchkpw /bin/true 2>&1
@400000004e9807b10dae2ca4 sslserver: fatal: unable to load certificate

I was completely puzzled initially by the error as the sertificate file /var/qmail/control/servercert.pem was an existing and properly self generated one. Besides that qmail daemontools init script /service/qmail-smtpd/run was loading the file just fine, where the same file failed to get loaded when sslserver command with the cert argument was invoked via /service/qmail-smtpdssl/run

It took me quite a while to thoroughfully investigate on what’s wrong with the new qmail install. Thanksfully after almost an hour of puzzling I found it out and I was feeling as a complete moron to find that the all issues was caused by incorrect permissions of the /var/qmail/control/servercert.pem file.
Here are the incorrect permissions the file possessed:

linux:~# ls -al /var/qmail/control/servercert.pem
-rw------- 1 qmaild qmail 2311 2011-10-12 13:21 /var/qmail/control/servercert.pem

To fix up the error I had to allow all users to have reading permissions over servercert.pem , e.g.:

linux:~# chmod a+r /var/qmail/control/servercert.pem

After adding all users readable bit on servercert.pem the file permissions are like so:

linux:~# ls -al /var/qmail/control/servercert.pem
-rw-r--r-- 1 qmaild qmail 2311 2011-10-12 13:21 /var/qmail/control/servercert.pem

Consequently I did a qmail restart to make sure the new readable servercert.pem will get loaded from the respective init script:

linux:~# qmailctl restart
* Stopping qmail-smtpdssl.
* Stopping qmail-smtpd.
* Sending qmail-send SIGTERM and restarting.
* Restarting qmail-smtpd.
* Restarting qmail-smtpdssl.

Now the annoying sslserver: fatal: unable to load certificate message is no more and all works fine, Hooray! 😉

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How to fix php “Fatal error: Class ‘SimpleXMLElement’ not found” and “Fatal error: Class ‘JLoader’ not found” on FreeBSD

Tuesday, June 21st, 2011

One of the contact forms running on a FreeBSD server configured to work on top of Apache+MySQL suddenly stopped working.

The errors that appeared on the webpage during a page request to the form url was:

Fatal error: Class 'SimpleXMLElement' not found in /var/www/joomla/plugins/system/plugin_googlemap2_helper.php on line 2176 Fatal error: Class 'JLoader' not found in /var/www/joomla/plugins/libraries/loader.php on line 161

As you see in the output the website which was causing the issues was running a Joomla version 1.5.23 Stable configured with RSForm!ver 1.5.x (as a contact form solution) and Google Maps version 2.13b plugins.

The Google Map from Google Maps plugin and the RSform were configured to appear on one physical configured article in Joomla and seemed to work just until now. However yesterday suddenly the error messages:
Fatal error: Class ‘SimpleXMLElement’ not found
Fatal error: Class ‘JLoader’ not found

came out of nothing, it’s really strange as I don’t remember doing any changes to either Joomla or the PHP installation on this server.
There is one more guy who has access to the Joomla installation which I suspect might have changed something in the Joomla, but this scenario is not very likely.

Anyways as the problem was there I had to fix it up. Obviously as the error message Fatal error: Class ‘SimpleXMLElement’ not found reported the server php simplexml was missing!

Just to assure myself the php simplexml extension is not present on the server I used the classical method of setting up a php file with phpinfo(); in it to check all the installed php extensions on the server.

Finally to solve the issue I had to install the module from ports php5-simplexml , e.g.:

freebsd# cd /usr/ports/textproc/php5-simplexml
freebsd# make install clean

Afterwards to make the new settings take place I did restart of my Apache server:

freebsd# /usr/local/etc/rc.d/apache2 restart
Syntax OK
Stopping apache2.
Waiting for PIDS: 63883.
Performing sanity check on apache2 configuration:
Syntax OK
Starting apache2.

Now my Joomla contact form is back to normal 😉

If someone has any idea why this error occured without any php or server modifications, and how comes that all worked fine beforehand even though I did not have the simplexml module instlaled on the server o_O, I would be enormously greatful.

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How to automatically reboot (restart) Debian GNU Lenny / Squeeze Linux on kernel panic, some general CPU overload or system crash

Monday, June 21st, 2010

If you are a system administrator, you have probably wondered at least once ohw to configure your Linux server to automatically reboot itself if it crashes, is going through a mass CPU overload, e.g. the server load average “hits the sky”.
I just learned from a nice article found here that there is a kernel variable which when enabled takes care to automatically restart a crashed server with the terrible Kernel Panic message we all know.

The variable I’m taking about is kernel.panic for instance kernel.panic = 20 would instruct your GNU Linux kernel to automatically reboot if it experiences a kernel panic system crash within a time limit of 20 seconds.

To start using the auto-reboot linux capabilities on a kernel panic occurance just set the variable to /etc/sysctl.conf

debian-server:~# echo 'kernel.panic = 20' >> /etc/sysctl.conf

Now we will also have to enable the variable to start being use on the system, so execute:

debian-server:~# sysctl -p There you go automatic system reboots on kernel panics is now on.
Now to further assure yourself the linux server you’re responsible of will automatically restart itself on a emergency situation like a system overload I suggest you check Watchdog

You might consider checking out this auto reboot tutorial which explains in simple words how watchdog is installed and configured.
On Debian installing and maintaining watchdog is really simple and comes to installing and enabling the watchdog system service, right afteryou made two changes in it’s configuration file /etc/watchdog.conf

To do so execute:

debian-server:~# apt-get install watchdog
debian-server:~# echo "file = /var/log/messages" >> /etc/watchdog.conf
debian-server:~# echo "watchdog-device = /dev/watchdog" >> /etc/watchdog.conf

Well that should be it, you might also need to load some kernel module to monitor your watchdog.
On my system the kernel modules related to watchdog are located in:

/lib/modules/2.6.26-2-amd64/kernel/drivers/watchdog/
If not then you should certainly try the software watchdog linux kernel module called softdog , to do so issue:
debian-server:~# /sbin/modprobe softdog

It’s best if you load the module while the softdog daemon is disabled.
If you consider auto loadig the softdog software watchdog kernel driver you should exec:

debian-server:~# echo 'softdog' >> /etc/modules

Finally a start of the watchdog is necessery:

 


debian-server:~# /etc/init.d/watchdog start
Stopping watchdog keepalive daemon....
Starting watchdog daemon....

That should be all your automatic system reboots should be now on! 🙂

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