Posts Tagged ‘domain name’

KVM Creating LIVE and offline VM snapshot backup of Virtual Machines. Restore KVM VM from backup. Delete old KVM backups

Tuesday, January 16th, 2024

kvm-backup-restore-vm-logo

For those who have to manage Kernel-Based Virtual Machines it is a must to create periodic backups of VMs. The backup is usually created as a procedure part of the Update plan (schedule) of the server either after shut down the machine completely or live.

Since KVM is open source the very logical question for starters, whether KVM supports Live backups. The simple answer is Yes it does.

virsh command as most people know is the default command to manage VMs on KVM running Hypervisor servers to manage the guest domains.

KVM is flexible and could restore a VM based on its XML configuration and the VM data (either a static VM single file) or a filesystem laying on LVM filesystem etc.

To create a snapshot out of the KVM HV, list all VMs and create the backup:

# export VM-NAME=fedora;
# export SNAPSHOT-NAME=fedora-backup;
# virsh list –all


It is useful to check out the snapshot-create-as sub arguments

 

 

# virsh help snapshot-create-as

 OPTIONS
    [–domain] <string>  domain name, id or uuid
    –name <string>  name of snapshot
    –description <string>  description of snapshot
    –print-xml      print XML document rather than create
    –no-metadata    take snapshot but create no metadata
    –halt           halt domain after snapshot is created
    –disk-only      capture disk state but not vm state
    –reuse-external  reuse any existing external files
    –quiesce        quiesce guest's file systems
    –atomic         require atomic operation
    –live           take a live snapshot
    –memspec <string>  memory attributes: [file=]name[,snapshot=type]
    [–diskspec]  disk attributes: disk[,snapshot=type][,driver=type][,file=name]

 

# virsh shutdown $VM_NAME
# virsh snapshot-create-as –domain $VM-NAME –name "$SNAPSHOT-NAME"


1. Creating a KVM VM LIVE (running machine) backup
 

# virsh snapshot-create-as –domain debian \
–name "debian-snapshot-2024" \
–description "VM Snapshot before upgrading to latest Debian" \
–live

On successful execution of KVM Virtual Machine live backup, should get something like:

Domain snapshot debian-snapshot-2024 created

 

2. Listing backed-up snapshot content of KVM machine
 

# virsh snapshot-list –domain debian


a. To get more extended info about a previous snapshot backup

# virsh snapshot-info –domain debian –snapshotname debian-snapshot-2024


b. Listing info for multiple attached storage qcow partition to a VM
 

# virsh domblklist linux-guest-vm1 –details

Sample Output would be like:

 Type   Device   Target   Source
——————————————————————-
 file   disk     vda      /kvm/linux-host/linux-guest-vm1_root.qcow2
 file   disk     vdb      /kvm/linux-host/linux-guest-vm1_attached_storage.qcow2
 file   disk     vdc      /kvm/linux-host/guest01_logging_partition.qcow2
 file   cdrom    sda      –
 file   cdrom    sdb      

 

3. Backup KVM only Virtual Machine data files (but not VM state) Live

 

# virsh snapshot-create-as –name "mint-snapshot-2024" \
–description "Mint Linux snapshot" \
–disk-only \
–live
–domain mint-home-desktop


4. KVM restore snapshot (backup)
 

To revert backup VM state to older backup snapshot:
 

# virsh shutdown –domain manjaro
# virsh snapshot-revert –domain manjaro –snapshotname manjaro-linux-back-2024 –running


5. Delete old unnecessery KVM VM backup
 

# virsh snapshot-delete –domain dragonflybsd –snapshotname dragonfly-freebsd

 

Configuring server running both OpenSSHD and Apache to be accessed via HTTPS

Friday, December 18th, 2009

I wanted to make this machine accessible for both me and others also with a simple browser,
I was thinking about configuring this on pc-freak since some time now.
It took me a while until I found a program that does this for me, anyhow luckily I found it.
It’s called webshell and is working pretty well. Check out the home page of WebShell for download and more info on it. I’ve succesfully installed it on FreeBSD 7.2.
All that is needed for the program to operate is python 2.3 or higher and python openssl (this is optional),
however most people would desire to have the service running over SSL thus this is mandatory.
On my FreeBSD box I had to install:
the port/package py26-openssl and subversion (this is a prerequirement in order to download the source via svn)
It also necessery to modify the webshell.py and change the shebang's location pointing to python
in freebsd that is:

#!/usr/local/bin/python and not #!/usr/bin/python

as in linux.
Then I copied the downloaded source to /usr/local/web-shell/webshell as well as add recordto rc.local

# echo "/usr/local/web-shell/webshell.py -d" >> /etc/rc.local The last thing I did was manually start the daemon with:
# /usr/local/web-shell/webshell.py -d

Tadam, it's up and running accessing it is as simple as pointing the browser
to a domain name or ip on which the python service is running
Currently the running webshell for pc-freak can be accessed via

Don’t revoke GoDaddy SSL certificate. (Expired) Revoked SSL is impossible to revert

Thursday, April 12th, 2012

godaddy_logo
One of our company SSL (https) Certificates recently expired so I needed to renew the SSL certificate.

I was in a hurry doing plenty of other stuffs so it seemed logical for me to Revoke the Certificate. I thought revoking the certificate will simply cancel it and afterwards, in Godaddy's SSL (Manager Certificates) interface the Revoked – Cancelled certificate will re-appear in the menu, ready to be generated in the same way as earlier I initially generated the Godaddy's bought SSL certificate

Hence I proceeded and used Revoke button:

Godaddy SSL certificate manager browser certificate Screenshot

Well guess what my calculations, were wrong.
 Revoking, just cancel it. The  revoked domain SSL certificate did not show up again in Godaddy's Cert Manager and I have no way from their interface to revert the changes.

To deal with the situation, I contacted Godaddy Support immediately with the following inquiry:
 

Other : Revoked SSL Certificate
Issue :
Hello we have revoked the SSL certificate for our domain our.domain-name.com.
 Can we revert back the certificate as it was.
If not how to generate a new key for our domain https://our.domain-name.com
Thanks in Advance.
Kindest Regards

"My-Company-name" Tech Support

In 5 hours time I received the following tech support answer:
 

Dear Tech Support,

Thank you for contacting Online Support. It is not possible to reinstate a canceled certificate. You will need to purchase a new certificate. I have requested that a refund be applied to your account. Once the credit appears in your account, please allow 5-7 business days to see the funds applied to the associated payment method. Thank you for your patience and understanding in this matter.

Please let us know if we can help you in any other way.

Sincerely,

Christian P.
Online Support Team
Customer Inquiry
Name : Cadia Tech Support
Domain Name : our.domain-name.com
ShopperID : xxxxxxxxx
Phone : xxxxxxxx
Shopper Validated : Yes
Browser : Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3

Apparently Godaddy, can work out a bit on their tech support answering time 5 hours for a simple reply is quite long.

Now taking in consideration, above reply from Godady, my only options are to either wait for 5 to 7 (business days) or buy a new credit for SSL certificate.

Buying a new credit will probably not happen as our company is experiencing some financial troubles because of the crisis. So I guess we will have to wait for this 7 days at worst. So again if you wonder to REVOKE or not an SSL certificate. Think again …

Just a small note to make here, that Godaddy has a very straight forward way to just renew an expered certificate, which I succesfully later have done for 4 domains. Well, if only I knew earlier what REVOKE SSL cert really does I wouldn't have ended in this mess …

What causes the “nRRPResponseCode 531” error, A fix to the nasty “nRRPResponseCode 531” error during domain name DNS change

Tuesday, March 16th, 2010

For two days now, I’m trying to set a custom DNS server for a (.net) domain purchased by gigaspark.com . Every time I try to change the nameservers for the (.net) domain an irritating error pops up, the error reads “nRRPResponseCode 531” and I cannot set my custom configured Bind DNS server for the (.net) domain. I believe the same problem happens also with (.com) domains.

In this relation, I tried googling online searching and searching what might be the stupid cause of the “nRRPResponseCode 531” error that prevents me from setting my custom configured Bind domain name servers to mydomain.net . I also contacted the support team from gigaspark multiply until I found out what is the trouble cause.
In short the “nRRPresponseCode 531” is an error that indicates your .net or .com domain is not figuring in VeriSign’s GRS domain database .
The Verisign GRS domain database contains a list of DNS servers that are correctly configured and trustworthy enough. I’ve seen many people online suffering from the same terrible error,
who pointed out that the error is caused by misconfigurations in the Bind DNS server or the zone file for the problematic domain name, though I’ve looked through multiple times to possibly track the problem in both my major named.conf and the rest of bind’s configuration files as well as in the domain name I had registered mydomain.net ,there was nothing misconfigured or unusual.
I have to admit, this problem is really odd, because I was able to successfully set the same custom configured Bind DNS server for mydomain.info and mydomain.biz but, yet whenever trying to set the same Bind DNS for mydomain.net I came across the shitty nrRRPResponseCode 531 .
Thanks to the kind help of Gigaspark’s tech support together with some google posts on the matter I figured out Gigaspark are using ENOM – a major domain name registrar offering easy ways for an end domain providers to become their resellers.
It seems ENOM’s policy is enforces you as a domain name customer to register your full DNS domain name let’s say (ns1.mydns.com) in Verisign’s GRS domain database otherwise they refuse you the right to set yourself your ns1.mydns.com for your domain, because if the DNS domain name is not figuring in that database it’s not trust worthy!
I believe many people would agree with me this is a real shit! You pay for your domain and you should have the full rights over it.
I mean you should be allowed to set whatever DNS domain name even, if it’s not an existing one and they shouldn’t bother you with stupid DNS domain name registrations in stupid Verisign GRS databases and so on!
Now you probably wonder what is the required steps to take to be able to register the domain in that Verisign GRS database in order to be able to set your ns1.mydomain.com as a default DNS server for your mydomainname.com .
Well you have to contact your domain registrar, let’s say gigaspark.com .
You log to your account on tucowsdomains for your domain mydomain.com … then you find something similar to: “register a nameserver” among the overall menus options.
Then you have to register your nameserver ns1.mydomain.com. Then you wait between 24 up to 48h and then you have to test if your NS has already properly entered the Verisign GRS database you have to visit on Verisign GRS Whois .
Hopefully the guys from Verisign GRS would approve your DNS host to enter there database and then at last you might be able to set in your DNS host as a preferred DNS for your (.net) / (.com?) domain name.
So go back to gigaspark’s slovenian interface and try changing the DNSes once again! If you’re lucky with God’s help (for sure), you would be at last be successful in setting your BIND name server as a primary DNS.

Howto install GeoTrust RapidSSL certificate on Debian Lenny / Squeeze / Wheezy Linux

Thursday, March 25th, 2010

I faced the task of generating official Validated SSL Certificates by in mydaily duties as a System Administrator at cadiaholding.com . Though generating self-signedSSL certificate is comparatively easy task. It was a pain in the ass setting Apache version 2.2.9-10+lenny6to correctly serve pages through https:// protocol over openssl version 0.9.8g-15+lenny6.I’ll try to go through the whole process of Generating the certificate in order to help some other Debianusers out there to face less setbacks in such a simple task as installing a Trusted SSL Certificate issued(bought) by RapidSSL. Even though this article will mostly deal with SSL certificate issued by RapidSSL,it should be not a problem to apply this methodogy with Verisign or some of the other Geotrust issuedSecure Socket Layer certificates.

In generating the Validated certficate I used enom which is a domain name,ssl certificates, email and hosting company whole-saler.
Fron emon’s website after logging in and using the web interface, there are two major things required to fill inin order to issue your Trusted SSL certificate.

1. Fill in in a form a CSR file, this is usually generated on the Linux server using the openssl.
To issue the CSR file required by Enom use the following commands:

a. First we generate an DES3 RSA encrypted key which we will use next to generate the opeensl CSR file required by ENOM.
debian:~# /usr/bin/openssl genrsa -des3 -out www.domain.com.key 2048
Enter pass phrase for www.domain.com.key:

You’ll be required to fill in a pass-phrase that will be later be required to fill in before Apache servers starts or restarts,so make sure you fill something you either remember or you keep the password stored in a file.
You have to change also the www.domain.com.key in accordance with your domain name.
Now as we already have a proper generated DES3 RSA key afterwards it’s necessery to generate the CSR file with the openssl command line frontend.
So here is how:

debian:~# /usr/bin/openssl req -new -key /home/hipo/www.domain.com.key -out /home/hipo/www.domain.com.csr

Again in the above example change all the paths and file names as you wish.
It’s necessery that the end user fill in a number of questions related to the Certificate Signing Request.
Herein I’ll list what kind of prompts will emerge after executing the above command:

Enter pass phrase for /home/hipo/www.domain.com.key:
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:
State or Province Name (full name) [Some-State]:
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (eg, YOUR name) []:
Email Address []:
Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

Note that you’ll hav eto fill in the pass phrase previously entered during the generation of the www.domain.com.key file.
In case if you’d like to read more thoroughly on the subject of howto create a Certificate Signing Request or (CSR) as we called it on multiple times, you can read About Certificate Signing Request (CSR) Generation Instructions – Apache SSL more in depth here

2. Hopefully following the above instructions you’ll now have a file named www.domain.csrJust open the www.domain.scr and copy paste it’s content to the ENOM website CSR * webform.

3. Further on select your Webserver type on Enom’s website:In our case we have to select Apache + ApacheSSL

4. What follows next is filling in your company contact information This is also required for proper certificate generation, you have to think twice before you fill in this data, take a note this can’t be changed later on without issuing a brand SSL new certificate.

Apart from the 3 major above requirements to fill in Enom there are some few more radio buttons to use to make some selections according to your personal preferences, however I won’t take time to dig in that and I’ll leave this to you.
After all the above is fulfilled you’ll have to submit your certificate details and choose an email address to which you will receive in a minute a RapidSSL Certificate Request Confirmation

Following a link from the email, will show you some basic information about the certificate about to be generated. That’s your final chance to cancel the issued Trusted Certificated.
If you’re absolutely sure the information about to enter the certificate is correct then you’ll have to follow a link and approve the certificate.

You’ll be informed that you’ll receive your certificate either through Certifier website (e.g. Enom’s website) or via another email.
I thought it’s more probable I receive it via email but anyways I was wrong. More thank 4 hours has passed since the certificate was issued and is available via Enom’s interface but I haven’t received nothing on my mail.
Therefore my friendly advice is to check about your brand new shiny Trusted Certificate on Emom’s website. I had mine ready in about 10 minutes after the CSR was issued.

Assuming that you’ve succesfully obtained the SSL Trusted certificate from RapidSSL what follows is setting up the certificate.
Initially I tried using documentation from RapidSSL website called Installing your SSL Certificate / Web Server Certificate / Secure Server Certificate from RapidSSL.com
I tried to configure one of my Virtualhost as shown in their example inserting in my /etc/apache/sites-available/www.domain.com file, few directives within the VirtualHost something like the shown below

SSLEngine on
# domain.com.crt cointains the Trusted SSL certificate generated and obtained by you from RapidSSL
SSLCertificateFile /etc/apache2/ssl/www.domain.com.crt
# www.domain.com.key contains the file used to generate the CSR file as described earlier in this post
SSLCertificateKeyFile /etc/apache2/ssl/www.domain.com.key

It is also possible insetad of using the SSLCertificateFile and SSLCertificateKeyFile directvies directives in Apache config to use:

 

Another alternative is to use

SSLCertificateFile /etc/ssl/certs/your-domain-name.crt
SSLCertificateKeyFile /etc/ssl/certs/your-domain-name.key
SSLCACertificateFile /etc/ssl/certs/gd_bundle.crt

The key file is the one generated earlier on the server and handed to the SSL regisrar, the files:

your-domain-name.crt and gd_bundle.crt files are provided by RapidSSL or from whatever SSL registrater the SSL was purchased.

After trying the above configuration and restarting apache with:

/etc/init.d/apache2 restart

Apache failed to start, it might be helpful to somebody out there the error I had in my apache error.log:
The error.log red the following:

[warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)

After some 30 minutes or an hour of Googling on the error I came to the conclusion that the error is caused, becauseApache is supposed to work with .PEM files instead of the classical .CRT and .KEY files asnormally approached in most of the other Unix operating systems.

It took me a bit more of reading on the internet to find out that actually the .pem files so widely adopted in Debian simply contain both the www.domain.com.key file and the www.domain.com.crt key simply pasted one after another, this I also observed from the default Apache self-signed certificate that I believe comes with debian /etc/apache2/ssl/apache.pem .
So I copied both the content of my www.domain.com.key and www.domain.com.crt and store it in one file:
/etc/apache2/ssl/www.domain.com.pem

Also the following configuration:
SSLEngine on
SSLCertificateFile /etc/apache2/ssl/www.domain.com.pem

had to go in your
/etc/apache2/sites-enabled/www.domain.com

Last thing that’s left is to restart your Apache;

/etc/init.d/apache2 restart

Apache will prompt you for your certificate password entered by you during the www.domain.com.key generation. Type your password and with a bit of luck and hopefully with God’s help you’ll be having a Trusted Certificate on your webserver.

Last step is to check if the certificate is okay accessing your domain https://www.domain.com.

Well this is the end of the article, hope you enjoy.If you do please leave your comments, any corrections are also welcomed 🙂

How to configure equivalent of Linux /etc/resolv.conf search domain.com in MS Windows – DNS Suffix

Thursday, June 26th, 2014

windows-append-dns-suffixes-on-windows-equivalent-of-linux-search-in-resolv-conf-screenshot

Linux's default file that defines what DNS servers will be used /etc/resolv.conf typically contains directives with the default search domain or domains; used for FQDN (Fully Qualified Domain Name) completion when no domain suffix is supplied as part of the  DNS query. Lets say sub-domains under domain.com  has to be accessed (in /etc/resolv.conf) there is:

search domain.com

That is very handy whether you have to ssh or open in web browser (sites) or multiple servers each residing under a single main domain name (for example:
server1.domain.com, server2.domain.com, server3.domain.com etc.) by typing in browser or SSH by only passing the sub-domain name i.e.:
 

http://server1
http://server2

or

ssh user@server1
ssh user@server2


Here is /etc/resolv.conf from www.pc-freak.net

# cat /etc/resolv.conf

domain www.pc-freak.net
search www.pc-freak.net bergon.net

 

Here is example of what I mean, ascii-games is a sub-domain of www.pc-freak.net (ascii-games.www.pc-freak.net) and is resolved with no need to type full FQDN

 

# host ascii-games
ascii-games.www.pc-freak.net has address 83.228.93.76


The DNS server knows that all failed to resolve queries by set DNS should be searched (resolved) under the defined search domain, i.e. each DNS query for server2, serverX (would try to be resolved as a subdomain of domain.com).

Therefore, a very good question is what is Microsoft Windows (2000, 2003, 8) OS equivalent way to define search domain.com into /etc/resolv.conf?

In Windows the same /etc/resolv.conf hosts search is done using the so called "DNS Suffixes".

DNS Suffixes are used for resolv of (domain name strings with no dots).

Adding a new DNS Suffix in Windows is done from

windows-control-panel-network-connections-screeshot-add-dns-suffix-equivalent-to-linux-resolv-conf-search

 

Control Panel -> Network and Sharing Center -> Change Adapter Settings

 

Here select LAN card Adapter used to bring Internet to Win host,be it Local Area Connection or

Wireless Network Connection

 and choose:

Properties


windows-append-dns-suffixes-on-windows-equivalent-of-linux-search-in-resolv-conf-screenshot

 

 

From

Network Connection Properties

dialog select

Internet Protocol Version 4 (TCP/IPv4)

and again click on

Properties

 


network-properties-internet-protocol-version4_tcp_ipv4-windows-settings-screenshot-advanced-tab-add-dns-suffix

On next dialog click on

 

Advanced (button) -> DNS (tab)

windows-append-dns-suffixes-on-windows-equivalent-of-linux-search-in-resolv-conf-screenshot


In field
 

DNS Suffix for this connection

fill in host which you would like to resolve with no need for FQDN and press the

Add


(exactly like adding search www.pc-freak.net in  /etc/resolv.conf on Linux host). Add multiple hosts DNS Suffix, if you want to access subdomains naming from multiple base domain.

Preserve domain name after redirect with mod_rewrite and some useful mod rewrite redirect and other examples – Redirect domain without changing URL

Friday, July 11th, 2014

redirect_domain_name_without_changing_url_apache_rewrite_rule_preventing_host_in_ip_mod_rewrite
If you're a webhosting company sysadmin, sooner or later you will be asked by application developer or some client to redirect from an Apache webserver to some other webserver / URL's IP, in a way that the IP gets preserved after the redirect.

I'm aware of two major ways to do the redirect on webserver level:

1. To redirect From Apache host A to Webserver on host B using ReverseProxy mod_proxy

2. To use Mod Rewrite to redirect all client requests on host A to host B.

There is quite a lot to be said and is said and written online on using mod_rewrite to redirect URLs.
So in this article I will not say nothing new but just present some basic scenarios on Redirecting with mod rewrite and some use cases.
Hope this examples, will help some colleague sys-admin to solve some his crazy boss redirection tasks 🙂 I'm saying crazy boss because I already worked for a  start-up company which was into internet marketing and the CEO has insane SEO ideas, often impossible to achieve …

a) Dynamic URL Redirect from Apache host A to host B without changing domain name in browser URL and keeping everything after the query in

Lets say you want to redirect incoming traffic to DomainA to DomainB keeping whole user browser request, i.e.

Redirect:

http://your-domainA.com/whole/a/lot/of/sub/directory/query.php


Passthe the whole request including /whole/a/lot/of/sub/directory/query.php

so when Apache redirects to redirect to:

http://your-domainB.com/whole/a/lot/of/sub/directory/query.php

In browser 
To do it with Mod_Rewrite either you have to add in .htaccess mod_rewite rules:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^your-domainA.com [OR]
RewriteCond %{HTTP_HOST} ^http://your-domainA.com
RewriteRule ^(.*) http://your-domainB.com/$1 [P]

or include this somewhere in VirtualHost configuration of your domain
 

Above mod_rewrite will make any request to your-domainA.com to forward to your-domainB.com while preserving the hostname in browser URL bar to old domain http://your-domainA.com, however still contet will be served by http://your-domainB.com
 

http://yourdomainA.com/YOUR-CUSTOM-REQUEST-ADDRESS


to redirect to

http://yourdomainB.com/YOUR-CUSTOM-REQUEST-ADDRESS


WARNING !!  If you're concerned about your SEO well positioning in search Engines, be sure to never ever use such redirects. Making such redirects will cause two domains to show up duplicate content
and will make Search Engines to reduce your Google, Yahoo, Yandex etc. Pagerank !!

Besides that such, redirect will use mod_rewrite on each and every redirect so from performance stand point it is a CPU killer (for such redirect using native mod_proxy ProxyPass is much more efficient – on websites with hundred of thousands of requests daily using such redirects will cause you to spend your  hardware badly  …)

P.S. ! Mod_Rewrite and Proxy modules needs to be previously enabled
On Debian Linux, make sure following links are existing and pointing to proper existing files from /etc/apache2/mods-available/ to /etc/apache2/mods-enabled

debian:~#  ls -al /etc/apache2/mods-available/*proxy*
-rw-r–r– 1 root root  87 Jul 26  2011 /etc/apache2/mods-available/proxy_ajp.load
-rw-r–r– 1 root root 355 Jul 26  2011 /etc/apache2/mods-available/proxy_balancer.conf
-rw-r–r– 1 root root  97 Jul 26  2011 /etc/apache2/mods-available/proxy_balancer.load
-rw-r–r– 1 root root 803 Jul 26  2011 /etc/apache2/mods-available/proxy.conf
-rw-r–r– 1 root root  95 Jul 26  2011 /etc/apache2/mods-available/proxy_connect.load
-rw-r–r– 1 root root 141 Jul 26  2011 /etc/apache2/mods-available/proxy_ftp.conf
-rw-r–r– 1 root root  87 Jul 26  2011 /etc/apache2/mods-available/proxy_ftp.load
-rw-r–r– 1 root root  89 Jul 26  2011 /etc/apache2/mods-available/proxy_http.load
-rw-r–r– 1 root root  62 Jul 26  2011 /etc/apache2/mods-available/proxy.load
-rw-r–r– 1 root root  89 Jul 26  2011 /etc/apache2/mods-available/proxy_scgi.load

debian:/etc/apache2/mods-avaialble:~# ls *proxy*
proxy.conf@  proxy_connect.load@  proxy_http.load@  proxy.load@


If it is is not enabled to enable proxy support in Apache on Debian / Ubuntu Linux, either create the symbolic links as you see them from above paste or issue with root:
 

a2enmod proxy_http
a2enmod proxy

 

b) Redirect Main Domain requests to other Domain specific URL
 

RewriteEngine On
RewriteCond %{HTTP_HOST} ^your-domainA.com
RewriteRule ^(.*) http://your-domainB.com/YOUR-CUSTOM-URL [P]

Note that no matter what kind of subdirectory you request on http://your-domain.com (lets say you type in http://your-domainA.com/My-monkey-sucks ) it will get redirected to:

http://your-domainB.com/YOUR-CUSTOM-URL

Sometimes this is convenient for SEO, because it can make you to redirect any requests (including mistakenly typed requests by users or Bot Crawlers to real existing landing page).

c) Redirecting an IP address to a Domain Name

This probably a very rare thing to do as usually a Domain Name is redirected to an IP, however if you ever need to redirect IP to Domain Name:

RewriteCond %{HTTP_HOST} ^##.##.##.##
RewriteRule (.*) http://your-domainB.com/$1 [R=301,L]

Replace ## with digits of your IP address, the is used to escape the (.) – dots are normally interpreted by mod_rewrite.

d) Rewritting URL extensions from .htm to .php, doc to docx etc.

Lets say you're updating an old website with .htm or .html to serve .php files with same names as old .htmls use following rewrite rules:. Or all your old .doc files are converted and replaced with .docx and you need to make Apache redirect all .doc requests to .docx.
 

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^(.*).html$ $1.php [NC]

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^(.*).doc$ $1.docx [NC]

The [NC] flag at the end means "No Case", or "case-insensitive"; Meaning it will not matter whether files are requested with capital or small letters, they will just show files if file under requested name is matched.

Using such a redirect will not cause Apache to redirect old files .html, .htm, .doc and they will still be accessible again creating duplicate content which will have a negavite impact on Search Engine Optimization.

The better way to do old extensioned files redirect is by using:

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^(.+).htm$ http://your-domainB.com/$1.php [R,NC]

[R] flag would tell make mod_rewrite send HTTP "MOVED TEMPORARILY" redirection, aka, "302" to browser. This would cause search engines and other spidering entities will automatically update their links to the new locations.

e) Grabbing content from URL with Mod Rewrite and passing it to another domain

Lets say you want zip files contained in directory files/ to be redirected from your current webserver on domainA to domainB's download.php script and be passed as argument to the script

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^files/([^/]+)/([^/]+).zip https://www.pc-freak.net/download.php?section=$1&file=$2 [R,NC]


f) Shortening URLs with mod_rewrite

This is ueful If you have a long URL address accessible via some fuzzy long hard to remember URL address and you want to make it acessible via a shorter URL without phyisally moving the files within a short named directory, do:

Options +FollowSymlinks
RewriteEngine On
RewriteRule ^james-brown /james-brown/files/download/download.php

Above rule would make requests coming to http://your-domain.com/james-brown?file=my.zip be opened via http://mysite/public/james-brown/files/download/download.php?file=my.zip

g) Get rid of the www in your domain name

Nowdays many people are used to typing www.your-domain.com, if this annoys you and you want them not to see in served URLs the annoying www nonsense, use this:

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{http_host} ^www.your-domain.com [NC]
RewriteRule ^(.*)$ http://your-domain.com/$1 [R=301,NC]

That's mostly some common uses of mod rewrite redirection, there are thousands of nice ones. If you know others, please share?


References and thanks to:

How to redirect domain without changing the URL

More .htaccess tips and tricks – part 2

 

 

Fix Apache [error] [client xx.xxx.xxx.xx] PHP Warning: Unknown: Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini. in Unknown on line 0

Wednesday, August 14th, 2013

I have a busy Linux server with 24 cores each running on ..4 Ghz. Server is configured to server  Apache and MySQL queries and a dozen of high traffic websites are hosted on it. Until just recently server worked fine and since about few days I started getting SMS notifications that server is inaccessible few times a day. To check what's wrong I checked in /var/log/apache2/error.log  and there I found  following error:

[error] [client 95.107.233.2] PHP Warning:  Unknown: Input variables exceeded 1000.

To increase the limit change max_input_vars in php.ini. in Unknown on line 0 referer: http://www.site-domain-name.com/predict/2013-08-10
 

Before I check Apache error.log, I had a guess that ServerLimit of 256 (spawned servers max) is reached so solution would be raise of ServerLimit to more than MaxClients setting defined in /etc/apache2/apache2.conf. After checking /var/log/apache2/error.log I've realized problem is because the many websites hosted on server exceed maximum defined variables possible to assign by libphp in php.ini. maximum possible defined variables before PHP stops servering is set through max_input_vars variable

As I'm running a Debian Squeeze Linux server, here is what is set as default for max_input_vars in /etc/php5/apache2/php.ini:

; How many GET/POST/COOKIE input variables may be accepted
; max_input_vars = 1000

So to fix it in php.ini just raised a bit setting to 1500, i.e.:

max_input_vars = 1500

Though I hit the error on Debian I assume same error occurs on Redhat RPM based (Fedora, CentOS, RHEL Linux) servers.
Hence I assume

max_input_vars = 1500

or higher should fix on those servers too. Looking forward to hear if same error is hit on RedHats.

Enjoy 🙂
 

Recovering long lost website information (data) with wayback machine

Monday, May 9th, 2011

Wayback machine, see 2 years old website from cache service

I needed a handy way to recover some old data of an expired domain containing a website, with some really imprtant texts.
The domains has expired before one year and it was not renewed for the reason that it’s holder was not aware his website was gone. In the meantime somebody registered this domain as a way to generate ads profit from it the website was receiving about 500 to 1000 visitors per day.
Now I have the task to recover this website permanently lost from the internet data. I was not able to retrieve anything from the old domain name be contained via google cache, yahoo cache, bing etc.
It appears most of the search engines store a cached version of a crawled website for only 34 months. I’ve found also a search engine gigablast which was claimed to store crawled website data for 1 year, but unfortunately gigablast contained not any version of the website I was looking for.Luckily (thanks God) after a bit of head-banging there I found a website that helped me retrieve at least some parts from the old lost website.

The website which helped me is called WayBack Machine

The Wayback Machine , guys keeps website info snapshots of most of the domain names on the internet for a couple of years back, here is how wayback machine website describes its own provided services:

The Internet Archive's Wayback Machine puts the history of the World Wide Web at your fingertips.

Another handy feature wayback machine provides is checking out how certain websites looked like a couple of years before, let’s say you want to go back in the past and see how yahoo’s website looked like 2 years ago.

Just go to web.archive.org and type in yahoo and select a 2 years old website snapshot and enjoy 😉

It’s really funny how ridiculous many websites looked like just few years from now 😉