1. Sync time with NTP(Network Time Protocol) server.

# which ntpdate

If its not display anything then type:

# yum install ntp

3. Once ntp is installed sync your system/server clock with any NTP server:

# ntpdate 0.us.pool.ntp.org

3. You are not limited to the above server. There are numerous NTP servers around the world. You can find a complete list at ntp.org. Also keep in mind that ntp only affects the system time. The hardware clock on your server will not reflect that. So you want to set it as well so that the correct time is maintained after reboot:

# hwclock –systohc

# ntpd

4. To keep your server clock automatically synchronized you can run the ntpd daemon which is installed as part of the ntp package. Edit the /etc/ntp.conf file to comment out the following lines:

# vi /etc/ntp.conf

——————————————–
#server 127.127.1.0     # local clock
#fudge  127.127.1.0 stratum 10
——————————————–

5. The above two lines can sometimes prevent ntpd from properly synchronizing your clock. They are already commented out by default on CentOS/RHEL 6. But on 5.x you have to comment them out manually. Finally type the following two commands to start the daemon and make it run automatically at boot up:

# service ntpd start

# chkconfig ntpd on

If you have WHM/cpanel installed on your server:-

Then login to WHM with the root details and go to Main >> Server Configuration >> Server Time

ANd click on sync time with time server,it will sync the server time with cpanel NTP server.

Also you can set the cron to server clock automatically synchronization with the following :-

0 9 * * * rdate rdate.cpanel.net

The above entry sync the server time at 9 o’clock every day with cpanel time server.

Enjoy Linux…

1. Once you  got the license confirmation, SSH to your cPanel server as root and run the following  command to aware your php with cpanel changes :-
#   /scripts/makecpphp

2. Download the latest installer using the command below:
#  cd /usr/local/cpanel/whostmgr/docroot/cgi/
#   rm -rf /usr/local/cpanel/whostmgr/docroot/cgi/rvsitebuilderinstaller/
#  rm -f rvsitebuilderinstaller.tar
#  wget http://download.rvglobalsoft.com/rvsitebuilderinstaller.tar
#   tar -xvf rvsitebuilderinstaller.tar
#  chmod 755 addon_rvsitebuilder.cgi
#   rm -f rvsitebuilderinstaller.tar

3. Open root WHM, at the bottom left menu under Plugins section, you will find RVSiteBuilder Installer menu.

4. Click RVSiteBuilder Installer to begin the installation process.

5. After complete the installation, you will be sent to RVSiteBuilder Manager automatically.Please configure RV SiteBuilder immediatly.

Done !!!!!!! Now Your cPanel should show the RVSiteBuilder as a feature in all cPanel users.

How to install RVSiteBuilder? If  server compiled with suhosin :-
You will need to increase the variable size in suhosin.Set the following suhosin options in your php.ini :-
———————————————————-
[suhosin]
; For translation manager to handle more inputs
suhosin.post.max_vars = 2000
suhosin.request.max_vars = 2000

; For URL handling
suhosin.request.max_totalname_length = 300
suhosin.request.max_varname_length = 300
suhosin.get.max_varname_length = 300
suhosin.get.max_name_length = 300
———————————————————

Increase the value as you need it. And don’t forget to restart apache.

Enjoy Linux… !!!

Today While accessing Awstats from Cpanel i have seen error below :-

———————————————————————-

Internal Server Error

open3: exec of /usr/local/cpanel/base/awstats.pl failed at cpsrvd-ssl line 6112

at /usr/lib/perl5/5.6.2/Carp.pm line 119

Carp::croak(’open3: exec of /usr/local/cpanel/base/awstats.pl failed’) called at /usr/local/cpanel/perl/IPC/Open3.pm line 230

IPC::Open3::_open3(’open3′, ‘main’, ‘GLOB(0xe20be50)’, ‘IO::Handle=GLOB(0xe338000)’, ‘>&ERRLOG’, ‘/usr/local/cpanel/base/awstats.pl’) called at /usr/local/cpanel/perl/IPC/Open3.pm line 291

IPC::Open3::open3(’GLOB(0xe20be50)’, ‘IO::Handle=GLOB(0xe338000)’, ‘>&ERRLOG’, ‘/usr/local/cpanel/base/awstats.pl’) called at cpsrvd-ssl line 6112

main::cgiHandler() called at cpsrvd-ssl line 1283

main::dodoc_cpaneld() called at cpsrvd-ssl line 1150

main::dodoc(’HASH(0xe04f60)’) called at cpsrvd-ssl line 963

—————————————————————————

Solution :-

Check the permission of /usr/local/cpanel/3rdparty/bin/awstats.pl file on the server.

It should be set as 755 that is executable by user, group and others.

Enjoy Linux… !!!!

In Linux….we use a whole partition of a physical hard disk for swapping. However, with the 2.6 Linux kernel, swap files are just as fast as swap partitions, although Red Hat recommends using a swap partition. Just Assume that you may upgrade the amount of RAM in your system from 1024 MB to 2048 MB, but there is only 2048 MB of swap space. It might be advantageous to increase the amount of swap space to approx 2 times of your physical RAM it means 4096 MB if you perform memory-intense operations or run applications that require a large amount of memory. The administrative flexibility of swap files outweighs that of partitions; since modern high capacity hard drives can remap physical sectors, no partition is guaranteed to be contiguous. You can add swap file as a dedicated partition or use following instructions to create a swap file.

You have three options: create a new swap partition, create a new swap file, or extend swap on an existing LVM2 logical volume. It is recommended that you extend an existing logical volume.

1. Extending Swap on an LVM2 Logical Volume :-

To extend an LVM2 swap logical volume login through root user (assuming /dev/VolGroup00/LogVol01 is the volume you want to extend):

1. Disable swapping for the associated logical volume:

# swapoff -v /dev/VolGroup00/LogVol01

2.  Resize the LVM2 logical volume by 2o48 MB:

# lvm lvresize /dev/VolGroup00/LogVol01 -L +2048M

3.  Format the new swap space:

# mkswap /dev/VolGroup00/LogVol01

4. Enable the extended logical volume:

# swapon -va

5. Test that the logical volume has been extended properly:

# cat /proc/swaps # free

2. Creating an LVM2 Logical Volume for Swap :-

To add a swap volume group login through root user (assuming /dev/VolGroup00/LogVol02 is the swap volume you want to add):

1. Create the LVM2 logical volume of size 2048 MB:

# lvm lvcreate VolGroup00 -n LogVol02 -L 2048M

2. Format the new swap space:

# mkswap /dev/VolGroup00/LogVol02

3. Add the following entry to the /etc/fstab file:

/dev/VolGroup00/LogVol02   swap     swap    defaults     0 0

4. Enable the extended logical volume:

# swapon -va

5. Test that the logical volume has been extended properly:

# cat /proc/swaps # free

3. Creating a Swap File :-

To add a swap file:

1. Determine the size of the new swap file in megabytes and multiply by 1024 to determine the number of blocks. For example, the block size of a 512 MB swap file is 524288 (1024 * 512MB = 524288 block size)

2. Through shell prompt as root, type the following command with count being equal to the desired block size:-

# dd if=/dev/zero of=/swapfile bs=1024 count=524288

3. Setup the  linux swap Area/file with the command:-

# mkswap /swapfile

4. To enable the swap file immediately but not automatically at boot time: -

# swapon /swapfile

5. To enable it at boot time, edit /etc/fstab to include the following entry: -

/swapfile          swap            swap    defaults        0 0

The next time the system boots, it enables the new swap file.

6. After adding the new swap file and enabling it, verify it is enabled by viewing the output of the command :-

#  cat /proc/swaps

Or

# free –m

# top

EAccelerator  is faster than APC. EAccelerator is “just” an opcode cache. It transparently caches PHP opcodes; all you have to do to use it is download, compile and enable and never worry about it again. APC, on the other hand, does a bit more. While APC also caches opcodes, it performs worse than EAC or xcache does (there’s a bit of debate as to which is better, for my particular needs, EAC was marginally faster, but both outperformed APC) for opcode caching. APC, on the other hand, also has some useful features that aren’t related to opcode caching, but rather apc_store, apc_fetch and apc_define_constants .Using PHP cache system will greatly increase your whole system performance, as you can with Pure PHP ned 209.58ms and using PHP cache system only need around 60ms. So it will boost your server response up to 4 times faster. And between XCache, APC and eAccelerator there are no significant different only 1ms-2ms different between them. So which one you choose is up to you, but if you use Zend Optimizer don’t use APC as they are not working together.

To install/Enable the APC please use this post.

]]> http://www.unixsurgeon.com/kb/diffrence-between-eaccelerator-apc-alternative-php-cache.html/feed 0 http://www.unixsurgeon.com/kb/make-apc-lo-error-1-apc-installation.html http://www.unixsurgeon.com/kb/make-apc-lo-error-1-apc-installation.html#comments Wed, 09 Mar 2011 12:09:37 +0000 admin http://www.unixsurgeon.com/kb/?p=244 Today when i try to install APC instead of EAccelerator via pecl install APC-3.1.5 or even WHM /Cpanel >> module installers >> php pecl >> manage

I get following error when the package comes to the make command:-

—————————————————————————–

running: make

/var/tmp/APC/apc.c:463: error: ‘apc_regex’ has no member named ‘preg’

/var/tmp/APC/apc.c:463: error: ‘apc_regex’ has no member named ‘preg’

/var/tmp/APC/apc.c:464: error: ‘apc_regex’ has no member named ‘nreg’

/var/tmp/APC/apc.c:464: error: ‘apc_regex’ has no member named ‘nreg’

make: *** [apc.lo] Error 1

ERROR: `make’ failed

————————————————————————————————–

To resolve this and reinstall the APC(make sure that EAccelerator removed from php),before reinstall the APC install the following packages :-

# yum install pcre-devel

before installing APC.

On Debian use

# aptitude install libpcre3-dev

Then you will get the following response when you reinstall the APC :-

—————————————————————————-

unixsurg [~]# cd /usr/lib/php/extensions/no-debug-non-zts-20090626/

unixsurg [/usr/lib/php/extensions/no-debug-non-zts-20090626]# ls

./ ../ apc.so

unixsurg [/usr/lib/php/extensions/no-debug-non-zts-20090626]# cat /usr/lib/php.ini |grep apc

extension=”apc.so”

unixsurg [/usr/lib/php/extensions/no-debug-non-zts-20090626]#

—————————————————————————–

]]> http://www.unixsurgeon.com/kb/make-apc-lo-error-1-apc-installation.html/feed 0 http://www.unixsurgeon.com/kb/how-to-kill-large-synflood-tcp-connections.html http://www.unixsurgeon.com/kb/how-to-kill-large-synflood-tcp-connections.html#comments Mon, 03 Jan 2011 17:21:57 +0000 admin http://www.unixsurgeon.com/kb/?p=196 Tcpkill :-   Tcpkill can be used to kill Tcp connections to or from a particular host, network, port, or combination of all. These programs take standard Berkeley Packet Filter (BPF) filters. This can be used for both port mirroring and arp spoofing.

Syntax :-

# tcpkill -i eth0 { expression }

Example :-

(a) Kill all outgoing ftp (port 21) connection:

# tcpkill -i eth0 port 21

(b) to prevent any connections to the host www.unixsurgeon.com or 2.2.4.8 :-

# tcpkill host 2.2.4.8

OR

# tcpkill host www.unixsurgeon.com

Options :-

-i

the -i option specify which interface you want the program to listen on. The default option interface on most computers is eth0, because most computers only have one interface.

-1 to 9

The -1 to -9 specify the degree of brute force you want the attack to use on the target, with -1 being the least brute and -9 being the most brute. Otherwise the command can be run without the -1 to -9 option or the -i option.

Tcpkill can be used to create a DoS attack within a WAN or LAN, and this can be done by using a sniffer like “dsniff “or “tcpdump” to look at the packets that are being transmitted and to pick a target that you want to deny service. Assume the target has been identified as 2.2.4.8, a simple command like:

# tcpkill host -9 2.2.4.8

Today after updating my php and apache on the server. I was getting 500 internal error my website and i got below error on my server apache error logs.

“/usr/bin/php: symbol lookup error: /usr/local/lib/php/extensions/no-debug-non-zts-20060613/suhosin.so: undefined symbol: zend_atol”

The error message appears when an old application or software is upgraded to latest version. It may not cause issues with all the applications but definitely does affect some of them.

The only works when you enable suhosin.simulation for the account instead of disabling suhosin on the server.

You can perform this task by following ways :-

1. By enabling suhosin.simulation in .htaccess file. If susphp is not enabled on the server.

php_flag suhosin.simulation On

2. By creating php.ini file under public_html/ directory. If susphp is enabled on the server.

suhosin.simulation On

If you are getting same error under wp-admin login page then copy your php.ini file under wp-admin/ directory and check once again.

Now you can check your application, Also there is no need to restart any service like apache….It will work…!!!

Your AWStats LogFormat parameter is: 1
This means each line in your web server log file need to have “combined log format” like this:
111.22.33.44 – - [10/Jan/2001:02:14:14 +0200] “GET / HTTP/1.1″ 200 1234 “http://www.fromserver.com/from.htm” “Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)”

And this is an example of records AWStats found in your log file (the record number 50 in your log):
118.94.161.217 – - [12/Sep/2010:21:18:04 +0530] “GET /adda/wp-content/uploads/avatars/1/75a71ca2ddfd423e7a9276ff8b6f22dd-bpthumb.jpg HTTP/1.1″ 200 1722

Setup (’/home/user/tmp/awstats/awstats.domain.com.conf’ file, web server or permissions) may be wrong.
Check config file, permissions and AWStats documentation (in ‘docs’ directory).
================================================== =======================

I have corrected it and use some trouble shooting steps :-

1. AWStats to perform the update manually, please try the following command (via root SSH access):-
# /scripts/runstatsonce
2. To update AWSTATS for particular user :-
# /scripts/runweblogs username
3. Just change the log format in user AWSTATS file :-
# vi /home/username/tmp/awstats/awstats.yourdomain.com.conf
change Logformat =4 instead of 1 or 2

Then update your AWSTATS through Cpanel or manually by step 2,you will get your AWSTATS updated.

Enjoy Linux..!!!!!

Standard Method :-

1. At the bottom of the cPanel interface, locate and click the “Cron Jobs” icon.

2. Click on the “Standard” tab.

3. The first option calls for you to enter the email address of where you want the results of the
cron job to be sent. Simply enter the email address in the provided field and move onto the next step.

4. For “Entry 1″ you will see the text “Command to run” with a text box beside. Input the command or path to the script you want to run in the field.

Example :- php -q /home/username/public_html/cron.php

5. Below “Command to run”, there are five options that will allow you the set the time and intervals for your cron job. Those options are listed as follows:

Minute(s)
Hour(s)
Day(s)
Month(s)
Weekday(s)

Once you create the Cron job, a confirmation page will be displayed stating “Cron Updated”.

6. After making the appropriate selections, click the “Save Crontab” button to create the entry. If you elect to reset the changes and go back to the default settings, simply click the “Reset Changes” button.

7. Click the “Go Back” tab and you will be redirected back to the main Cron Job screen.

8. Check your email address to view the results of the cron job.

Advanced Method :-

1. From the main Cron Job screen, click the “Advanced (Unix Style) tab.

2. The first option calls for you to enter the email address of where you want the cron job results to be sent. Simply enter the email address in the provided text box.

3. From there, enter the Minute(s), Hour(s), Day(s), Month(s) Weekday and Command in the provided text boxes.

4. Next, click the “Save Crontab” button to create the entry. If want to the reset the changes and revert back to the default settings, simply click the “Reset Changes” button.

5. A confirmation page will be displayed stating “Cron Updated!” Click the “Go Back” button and you will be redirected back to the main Cron Job screen.

6.) Check your email address to view the results of the cron job.

If you want to benefit from cron jobs and use them effectively, you will need to have some familiarity with Linux commands. This is especially true when creating cron jobs in the Advanced Unix variation. For this reason, it is recommended to inquire within your web host about the files and scripts you want to run before executing them.

Enjoy Linux..