wget http://www.configserver.com/free/cmq.tgz

Untar the file using the below command

tar -xzf cmq.tgz

cd into the directory created and run the install script:

cd cmq/
sh install.sh

Login to WHM and scroll to the bottom of the left hand menu and you should see “ConfigServer Mail Queues”

Uninstall

Delete the below files.

rm -fv /usr/local/cpanel/whostmgr/docroot/cgi/addon_cmq.cgi
rm -fv /usr/local/cpanel/whostmgr/docroot/cgi/cmqversion.txt
rm -Rfv /usr/local/cpanel/whostmgr/docroot/cgi/cmq/

** phase 1 – Check Blocks and Sizes
** phase 2 – Check Pathnames
** phase 3 – Check Connectivity
** phase 4 – Check Reference Counts
** phase 5 – Check Cylinder Groups

Procedure
=======
1) Take system down to runlevel one (make sure you run all command as root user):

# init 1

2)Unmount file system, for example if it is /home (/dev/sda3) file system then type command:

# umount /home

3) Now run fsck on the partition:

# fsck -fyC /dev/sda3

y- Display completion/progress bars for those filesystem checkers (currently only for ext2 and ext3) which support them
C - to fix any detected filesystem corruption automatically

4) Once fsck finished, remount the file system:

# mount /home

5) Go to multiuser mode

# init 3

Additional examples
----------------------

1. Run through the /etc/fstab file and try to check all file systems in one run.

#fsck -A 

To run the VNC Server on CentOS, we have to install these required packages:

yum groupinstall Desktop
yum install tigervnc-server
yum install xorg-x11-fonts-Type1
yum install vnc

To start VNC Server on boot

chkconfig vncserver on

To setup users’ VNC password:

vncpasswd

Edit the /etc/sysconfig/vncservers file:

nano /etc/sysconfig/vncservers

Add the following to the end of the file:

VNCSERVERS="1:arbab"
VNCSERVERARGS[1]="-geometry 1024x600"

The iptables rules need to be amended to open the VNC ports:

iptables -I INPUT 5 -m state --state NEW -m tcp -p tcp -m multiport --dports 5901:5903,6001:6003 -j ACCEPT
service iptables save
service iptables restart

Restart the VNC Server:

service vncserver restart

Now kill the VNC Server:

vncserver -kill :1

Edit the xstartup file in .vnc directory:

nano .vnc/xstartup

Comment the last line and run the Gnome:

#twm & 
exec gnome-session &

Restart the service:

service vncserver restart

Now, download VNCViewer onto our desktop computer from which we want to access the shared desktop.
Connect using ServerIP/Name:1 (:1 is for the VNC server window)

http://www.realvnc.com/download/viewer/


Enter the password that we created using the vncpasswd command:

Ability to connect for multiple users:

Create a local user, using the following command:

adduser ali

Create a password for newly created user:

passwd ali

Switch to the newly created user and run vncpasswd command for it:

su ali

vncpasswd

Edit the /etc/sysconfig/vncservers file:

nano /etc/sysconfig/vncservers

Add these lines for new user:

VNCSERVERS="1:arbab 2:ali"
VNCSERVERARGS[1]="-geometry 1024x600"
VNCSERVERARGS[2]="-geometry 1024x600"

Restart the VNC service:

service vncserver restart

Kill the vncserver session for new user and edit the xstartup file:

su ali
vncserver -kill :2
cd ~
nano .vnc/xstartup

Modify the file so it looks like this:

#twm & 
exec gnome-session &

Restart the VNC service:

service vncserver restart

Connect with newly created user using centos:2, Where centos is my server name:

Enter the password that we created using the vncpasswd command:

1. First backup current network configuration

#cp /etc/network/interfaces /etc/network/interfaces.backup

How to delete an ipv6 address :  #ifconfig eth0 inet6 del 2604:2881::8fe5:27e2/64

How to add an ipv6 address :  #ifconfig eth0 inet6 add 2604:2881::8fe5:27e2/64

2. Add an IPv6 route through gateway

#route -A inet6 add 2604:2880::8fe5:27e2/64 gw <gateway ip>
OR
#ip -6 route add 2604:2880::8fe5:27e2/64 via <gateway ip>
#/etc/init.d/networking restart

to see the new ipv6 address :

#ip -6 address show eth0

to see ipv6 route :

# ip -6 route show dev eth0

To Permanently add IPV6 to the server, follow the below steps:

Append the below lines in "/etc/network/interfaces" file.

#vi /etc/network/interfaces

iface eth0 inet6 static
pre-up modprobe ipv6
address 2604:2880::8fe5:27e2/64
netmask 64
gateway 2247:f0d0:2001:000a:f0d0:2001::1
dns-nameservers 2001:4860:4860::8888 2001:4860:4860::8844

If ipv6 nameserver IPs are not there in /etc/resolv.conf then add Google Public DNS IPv6 addresses

nameserver 2001:4860:4860::8888
nameserver 2001:4860:4860::8844

#route -A inet6 add 2604:2880::8fe5:27e2/64 gw 2247:f0d0:2001:000a:f0d0:2001::1

#/etc/init.d/networking restart

To test ipv6 connectivity :

#ping6 google.com

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

(2) Redirecting a domain to another domain via .htaccess

Example :- redirect domain.com to google.com

RewriteEngine on
RewriteCond %{HTTP_HOST} ^domain\.com$ [OR]
RewriteCond %{HTTP_HOST} ^www\.domain\.com$
RewriteRule ^/?$ “http\:\/\/www\.google\.com\/” [R=301,L]

(3)  Redirect users to access the site with WWW

example :- redirect domain.com to www.domain.com

add the below in .htaccess file

RewriteEngine on
RewriteCond %{HTTP_HOST} ^domain\.com$ [NC]
RewriteRule ^(.*)$ http://www.domain.com/$1 [L,R=301]

(4)  Redirect page to another page within public_html

example1 :- to redirect home.html to index.php

RewriteEngine on
RewriteRule ^home.html$ index.php

example2 :-  rewrite site  http://domain.com/kb/index.php  to   http://domain.com/blog/index.html

go to kb directory and create a .htaccess file

#cd public_html/kb
#touch .htaccess
#vi .htaccess

RewriteEngine on
RewriteRule ^index.php$ /blog/index.html

rdate -p rdate.cpanel.net

rdate -s rdate.cpanel.net

-p Print the time returned by the remote machine.

-s Set the system time to the returned time

Now on the subnode run the below commands

rm -f /etc/localtime

ln -s /usr/share/zoneinfo/{desired-timezone} /etc/localtime

Use the command date to verify its working.

If you want to set the time in an OpenVZ sub node from main node, execute the following command on the HW node:

vzctl set VZID --capability sys_time:on --save

vzctl restart VZID

vzctl enter VEID

date (to check the time)

Go to zpanel > Admin > moduleAdmin >DNS config >Tools > Force Records Update on Next Daemon Run

Then run the daemon by going to

Admin > Zpanelconfig> Run Daemon now option in the top bottom of it.

Also location of named.conf in zpanel is /etc/zpanel/configs/bind/etc/named.conf and /etc/zpanel/panel/local/zpanel/etc/build/config_packs/centos_6_2/bind/etc/named.conf

The location of zone files is /etc/zpanel/configs/bind/zones

All zone files and dns files should have user and group as apache.

To avoid the named.conf going blank while adding new domains, do the following:

1) Log into zpanel

2) Go into the Module Admin

3) Click the DNS Config link

4) Edit this config option in the general tab:

Named CheckZone

FROM

named-checkzone

named-checkconf

named-compilezone

TO

/usr/sbin/named-checkzone

/usr/sbin/named-checkconf

/usr/sbin/named-compilezone

Enable the core patterns you need and run the below command to reflect the changes.

sysctl -p

In most Linux distributions, core dump file size defaults to '0' which disables the core dump generation. You can check the same using the below command:

root@whr [~]# ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 57344
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 57344
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

For the SSH session you are in, you can enable core dumps using the below command:

ulimit -c unlimited

Check the results again and you will see that file size is now unlimited. But as mentioned earlier, it will only be unlimited for the current SSH session.

root@whr[~]# ulimit -a
core file size          (blocks, -c) unlimited
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 57344
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 57344
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

To enable it for all users on all sessions, you need to set that in /etc/security/limits.conf file.

echo "*  soft  core  unlimited" >> /etc/security/limits.conf

If you are on a OpenVz/Virtuozzo node, make sure this is enabled in the main node. Enjoy dumping!!

Pre-requisists:

• MySQL version must be upgraded to 5.1

• PHP 5.2 version should be atleast 5.2.17

mkdir /usr/local/buildphp53

cd /usr/local/buildphp53

wget http://us3.php.net/get/php-5.3.13.tar.gz/from/us.php.net/mirror

tar --strip-components=1 -zxvf php-5.3*

./configure --prefix=/usr/local/php53 --enable-cgi --enable-bcmath --enable-calendar --with-mysql=mysqlnd --with-mysqli=mysqlnd and --with-pdo-mysql=mysqlnd --enable (all the modules you need)

           

/usr/bin/make

/usr/bin/make install

 

Extra configurations required

For Apache:

 vi /usr/local/apache/conf/includes/pre_virtualhost_global.conf

Add the following lines to the above file and save

 

Action application/x-httpd-php53 /cgi-sys/php53

 AddType application/x-httpd-php53 .php53

 

 To make cPanel skip the .htacces scan and remove the mime types, do the  following

 

/usr/local/cpanel/bin/apache_conf_distiller --update

touch /var/cpanel/easy_skip_update_php_mime_types 

vi /usr/local/cpanel/cgi-sys/php53

Add the following contents to the above file and save 

 

#!/bin/sh
 exec /usr/local/php53/bin/php-cgi

Setting Permissions

chown root:wheel /usr/local/cpanel/cgi-sys/php53

chmod +x /usr/local/cpanel/cgi-sys/php53

 Soft-linking for command-line executions:

 ln -s /usr/local/php53/bin/php-cgi /usr/local/bin/php53

 Copying php.ini from build folder 

 

mv /usr/local/buildphp53/php.ini-production /usr/local/php53/lib/php.ini

You need to restart httpd after the configuration 

 

/etc/init.d/httpd restart

 Now everything is set. If you want to enable php5.3 for a particular account, create a .htaccess file as mentioned below. 

 

nano -w /home/$username/public_html/.htaccess

Add the following line to it

 

AddHandler application/x-httpd-php53 .php

 Correct the permissions;

 

chown $username:$username /home/$username/public_html/.htaccess
 

chmod 644 /home/$username/public_html/.htaccess

 

 Things you should remember while installing/enabling a new module to new custom build php 5.3

•   Make sure that you do things related to php5.3 . For eg, if you have to do a “phpize”, you have to do it like this in command-line.

 

/usr/local/php53/bin/phpize

• If you want to run ./configure, select the correct php-config path. See the example given below.

./configure  --with-php-config=/usr/local/php53/bin/php-config

 That's all.

sysctl -w net.ipv4.netfilter.ip_conntrack_tcp_timeout_syn_recv=45

sysctl -w net.ipv4.netfilter.ip_conntrack_tcp_timeout_established=332000

sysctl -w net.ipv4.tcp_fin_timeout=15

sysctl -w net.ipv4.tcp_synack_retries=5

sysctl -w net.ipv4.tcp_fin_timeout=15

sysctl -w net.ipv4.tcp_keepalive_time=1500

sysctl -w net.ipv4.tcp_sack=0

sysctl -w net.ipv4.tcp_max_tw_buckets=1440000

sysctl -w net.ipv4.tcp_max_syn_backlog=2048

sysctl -w net.ipv4.tcp_max_syn_backlog=4096

sysctl -w net.ipv4.tcp_fin_timeout=20

sysctl -w net.ipv4.tcp_keepalive_time=1800

sysctl -w net.ipv4.tcp_fin_timeout=20

sysctl -w net.ipv4.tcp_keepalive_time=1800

sysctl -w net.ipv4.tcp_keepalive_intvl=40

sysctl -w net.ipv4.tcp_tw_recycle=1

sysctl -w net.ipv4.tcp_tw_reuse=1

sysctl -w net.ipv4.tcp_max_syn_backlog=4096

sysctl -w net.ipv4.inet_peer_gc_maxtime=240

sysctl -w net.ipv4.inet_peer_maxttl=500

sysctl -w net.ipv4.inet_peer_minttl=80

We will be adding more sysctl tweaks soon.

If the DDOS attack is large, there is nothing you could do to fully mitigate it. But the first thing you should do is to understand the nature of the DDOS attack and the targeted site/service.

Finding the target will really help if the site is hosted in a shared server. One of the effective way to mitigate the DDOS attack is to use a hardware firewall along with the software firewall.

Popular data centers like SoftLayer/The Planet, DedicatedNow use Cisco, Riorey respetively for large DDOS attacks and are quite effective (as far as I have experienced). If the attack prevails for a long time and if it reaches the threshold value, it would be better to null-route the IP under attack for a period of 4-5 hours.

Another suggested method is to increase the port speed of your server to a higher one, say if your current port speed is 10Mbps or 100Mbps, upgrade to 1000Mbps.

Here we will be discussing steps to mitigate it in a LAMP server using some Apache settings/modules, software firewalls and TCP/IP tweaks.

Click here to find Apache module tweaks and Click here to find kernel tweaks to mitigate DDOS and SYN floods.

* Product names, logos, brands, and other trademarks featured or referred within the page are the property of their respective trademark holders. These trademark holders are not affiliated with webhostrepo.com or our products.

Assume we have a server with 2GB memory

Total memory: is the available physical RAM in the server. In this case 2GB.

Operating System Memory: Stop Apache and MySQL in the server to calculate the actual memory used by OS (rough figure) using the below command:

ps aux | awk '{sum1 +=$4}; END {print sum1}'

In our test VPS:

root@whr [~]# ps aux | awk '{sum1 +=$4}; END {print sum1}'
37.2

Then restart Apache and MySQL and wait for a while to get the apt results for Apache and MySQL memory utilization.

Now we will see steps to calculate the MySQL memory utilization:

MySQL memory:

You will come across a lot of calculations for MySQL usage, but the one I found somewhere near was:

mysql_memory= (key_buffer_size + query_cache_size + innodb_buffer_pool_size + innodb_additional_mem_pool_size + innodb_log_buffer_size + max_connections + tmp_table_size) x (sort_buffer_size + read_buffer_size + join_buffer_size + read_rnd_buffer_size + thread_stack + binlog_cache_size)

In test VPS the default values were:

64+64+8+1+1+150+32 * 2+.128+.256+.128+.196+0 = 866.56MB used by MySQL

Size per Apache process: Normally between 20-25MB if you run dynamic websites.

MaxClients is, 2048 - (37.2+ 866.56)/20 ~= 57.

If you increase this value, you will see your server swapping often, so either maintain this value for MaxClients or increase the physical memory (RAM).

The first thing to do is to use a tool like "ab" for performance benchmarking:

ab -n 500 -c 10 http://www.domain.com/index.html

where n is: number of requests and c is the concurrency level. Run the command before and after the performance tuning and analyze the output. You need to check if the time taken by the webserver to deliver the result has improved.

1. Apache modules and settings

a) mod_reqtimeout

Syntax:

RequestReadTimeout [header=timeout[-maxtimeout][,MinRate=rate] [body=timeout[-maxtimeout][,MinRate=rate]

As seen above, time outs can be set for both request header and body from the client. Set this to a low value to make sure both header and body times out after the configured time.

b) TimeOut

This directive defines the time that Apache process will wait for I/O. The default value is set to 60 seconds and you should lower it to say 10-20 seconds in case of DDOS attacks. Some cgi scripts that need more execution time may face issues due to this.

c) KeepAlive and KeepAliveTimeout

Most of the webhosts disable KeepAlive during DDOS but doing so affects the server's performance again. A better idea would be to decrease the KeepAliveTimeout to 2 (default 5) and still have the KeepAlive enabled.

d) LimitRequestBody

This defines the allowed size of message body to be allowed. During DDOS attacks, set this server-wide. The default value is 0 which means unlimited. Set that to 100MB and see if improves the performance.

Syntax:

LimitRequestBody value

LimitRequestBody 102400000

e) LimitRequestFields

This directive limits the request header fields from the client. Set this to a value between 40-50
LimitRequestFields 40 (default is 100)

f)  LimitRequestFieldSize

This limits the size of the HTTP request header allowed from the client. Default is 8190 and is hard coded when it is recompiled. Decrease this value to half.

LimitRequestFieldSize 4095

g)  LimitRequestLine

This limits the size of the HTTP request line that will be accepted from the client.

LimitRequestLine 4095 (default is 8190)

h)  LimitXMLRequestBody

This limits the size of an XML type body request.

LimitXMLRequestBody 500000 (defaults to 1000000)

i) MaxRequestWorkers

A webserver should never use SWAP as doing so further decreases the server's performance and increases the server load drastically. You should regulate this directive to make sure that Apache doesn't spawn so many child processes as it starts swapping.

j) ServerLimit

It is the upper limit for the number of connections configured for Apache.

k) MaxClients

It is the maximum number of simultaneous connections that will be processed by Apache web server. This value should never exceed the #ServerLimit set. Extra care should be taken into consideration while setting the MaxClients value as any slight variation could badly affect the overall server's performance.

Click here to know how to calculate the Apache MaxClients value

>> ffmpeg

ffmpeg: error while loading shared libraries: libavdevice.so.52: cannot open shared object file

Which means the file is either missing or the server was unable to locate the libraries path,

Locate the file using

>> find / -iname libavdevice.so.52

If you get an output, enter the location of the library to the ld.so.conf file.

>> vi /etc/ld.so.conf

Say, if the library is located at /opt/lib/libavdevice.so.52.so, add /opt/lib to ld.so.conf file.

After adding the path to the library, run the below command to make sure the system takes the library path.

>> ldconfig -v

vi /var/cpanel/cpanel.config

check disk_usage_include_sqldbs=0 and change it to disk_usage_include_sqldbs=1, if the line noe found, simply add it to the bottom.

You can do the same via WHM >> Main >> Server Configuration >> Tweak Settings >> SQL >>

/scripts/update_db_cache

Often the stepping stone for a successful team management is to have a learning curve for both the team members and leaders. Learning curve could be any factor that enables to contribute towards desirable outcome or it could be what not to do...

Team can be anywhere: at your family, at your office, in a play ground or it could a team party…
Where ever it is, every one will work towards a common goal but with different strategies and tactics. Depends upon what coin is you in the plot then- Plan Act and Review. …

In short Successful team will have a definite Planning they will Act willingly and timely fashion and learn through Review's and feed backs.

Issue:

http://domain.com/sample.exe shows 404 error.

Add the following lines to your web.config file inside <system.webServer> tag

<system.webServer>

<handlers>
<add name=”Client exe" path="*.exe" verb="*" modules="StaticFileModule" resourceType="File" />
</handlers>

</system.webServer>

If you have local/remote access to IIS manager, you can add mimetype via IIS.

If you have WebSitepanel control panel, you can do that via control panel >> Websites >> websites properties >> Mime >> on the "Extensions" field add .exe and on "MIME-Type" add application/octet-stream

Done

Also note that it was the WHMCS main server that was hacked as a result of social engineering while the software as such is not open to any sort of vulnerability.

We can however apply patches to your existing WHMCS if required and also secure the admin portal without any additional fee.

If you are running WHMCS, use the coupon code WHMCS50 while ordering. This offer/coupon code is valid only till 05/31/2012.

New Update:

Vision Helpdesk is newly released software, owned and operated by ThinkSoftwares.net. The helpdesk software offers effective methods for managing emails, troubleshooting, news, downloads, and more.

We believe that with this new partnership, we would be able to provide our existing and new potential webhosting customers with a highly featured helpdesk software free for one year.

If you are an existing customer of ours and are planning to switch to Vision Helpdesk from the below helpdesk softwares, we provide free migration assistance.

• Kayako Support Suite
• Kayako eSupport
  
• Cerberus
• WHMCS

Leaves/year = 20days (160 hours)

Network outage/year (ISP issues) = 20 hours

Power outage/month = 30 hours

If the hourly rate is $10/hour, you will have a loss of USD $2100 for a single tech. It will be a huge amount if the number of techs is more. If the operations are handled by an outsoured firm it becomes their headache to make sure your requirement for support team is met.