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Adding IP Addresses CentOS

You will need to be the root user and navigate to: /etc/sysconfig/network-scripts

# cd /etc/sysconfig/network-scripts

When getting a list of files in the directory you will see "ifcfg-eth0" (or eth1 if you're doing it for a different adapter)

Now adding the virtual adapters is easy. Basically if the main adapter is called "eth0" you have to call the next (virtual) adapter in a sequential order like so:

  • ifcfg-eth0 (primary adapter, physical)
  • ifcfg-eth0:1 (first virtual adapter to the physical primary adapter)
  • ifcfg-eth0:2 (second virtual adapter to the physical primary adapter)
  • and so on...

That being said, lets go ahead and copy our primary adapter configuration file and name it to be the first virtual adapter for the physical primary:

# cp ifcfg-eth0 ifcfg-eth0:1
# ls -l | grep ifcfg-eth
-rw-r--r-- 1 root root   119 Jan 11 19:16 ifcfg-eth0
-rw-r--r-- 1 root root   119 Feb 24 08:53 ifcfg-eth0:1
-rw-r--r-- 1 root root   119 Jan  3 08:45 ifcfg-eth0.bak
-rw-r--r-- 1 root root   119 Feb 24 04:34 ifcfg-eth1
-rw-r--r-- 1 root root   128 Jan 19 18:20 ifcfg-eth1.bak

Now, we have to configure this virtual adapter to be: a static IP (of course), no hardware address (MAC), configure netmask and of course rename the device.

# vim ifcfg-eth0:1

There is no need to specify a MAC address as it is a virtual adapter and there is also no need to specify a default gateway as it is already routed through the primary adapter. Basically there are only four things that you will need to change:

  • File name for the adapter itself
  • DEVICE=<device name> (should correspond with the file name)
  • IPADDR=<ip address>
  • NETMASK=<netmask>

Afterwards, just restart the networking service:

# service network restart

That's it; lets check ifconfig to make sure the virtual adapter is there and working:

# ifconfig eth0:1
eth0:1    Link encap:Ethernet  HWaddr 08:00:27:ED:05:B7
inet addr:  Bcast:  Mask:

# ping
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=0.073 ms
64 bytes from icmp_seq=2 ttl=64 time=0.042 ms
64 bytes from icmp_seq=3 ttl=64 time=0.029 ms
64 bytes from icmp_seq=4 ttl=64 time=0.029 ms
--- ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 2999ms
rtt min/avg/max/mdev = 0.029/0.043/0.073/0.018 ms

Per Steven's comment: a second note. If you're not sure if you've done it right and you do not want to restart the entire network server, you can use the following:

# ifup eth0:1
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How to disable RC4 cipher in Apache/ disable RC4 cipher in Amazon load balencer

One of the site security scan report shows me that our webserver has vulnerabilities as it is supporting RC4 cipher in SSL/TLS encryption. So how to disable it?

Disabling RC4 cipher in Apache webserver.

Here are the two steps:

1. Add this line on “/etc/sysconfig/httpd” file (I’m using RedHat OS)


2. Add the following lines in your virtualhost area created for https.

SSLProtocol ALL -SSLv2 -SSLv3
SSLHonorCipherOrder On
SSLCompression Off

Now you almost done !! You can verify it over https://www.ssllabs.com/ssltest/analyze.html

In my case, I’m still getting the same error showing that it is still enabled. Here is the trick, I got to know that Amazon Elastic Loadbalencer is doing SSL acceleration for my project and this should be done on that area.

a. Go to Loadbalencer area and choose your LB, Click on “Change cipher
b. Choose “Custom LB policy”
c. Un check RC4-SHA and ECDHE-ECDSA-RC4-SHA and save

Then re-run the SSL lab test and you will see the result finally !!


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How to install Memcache and Memcached on WHM/cPanel

Without wasting much time, Let us get started!

Follow these simple instructions to install Memcache and Memcached:

Step 1: Login into your WHM panel and using easyapache enable Memcache (you must recompile apache)

Step 2: SSH into your server and fire this command:
yum install memcached.x86_64 php-pecl-memcache.x86_64

Step 3: Go to Software -> Module Installers -> PHP Pecl, Search for memcache and then install both memcache & memcached

Step 4: Restart apache once, Fire: service httpd restart

Step 5: Start memcache by firing this command: memcached -d -m 512 -l -p 11211 -u nobody
(d = daemon, m = memory, u = user, l = IP to listen to, p = port)

Step 6: Check your memcached server is running successfully: ps -eaf | grep memcached

All Done! If everything goes good, You should now be able to use memcached within your application.

Enjoy Caching!


make: *** [ffmpeg_frame.lo] Error 1 – error when installing ffmpeg-php

If you're obtaining the subsequent error whereas aggregation the most recent unharness of ffmpeg-php-0.6.0 , this article will allow you to savvy to induce this fix.


/usr/src/ffmpeg-php-0.6.0/ffmpeg_frame.c: In function âzim_ffmpeg_frame_toGDImageâ:
/usr/src/ffmpeg-php-0.6.0/ffmpeg_frame.c:336: error: âPIX_FMT_RGBA32â undeclared (first use in this function)
/usr/src/ffmpeg-php-0.6.0/ffmpeg_frame.c:336: error: (Each undeclared identifier is reported only once
/usr/src/ffmpeg-php-0.6.0/ffmpeg_frame.c:336: error: for each function it appears in.)
/usr/src/ffmpeg-php-0.6.0/ffmpeg_frame.c: In function âzim_ffmpeg_frame_ffmpeg_frameâ:
/usr/src/ffmpeg-php-0.6.0/ffmpeg_frame.c:421: error: âPIX_FMT_RGBA32â undeclared (first use in this function)
make: *** [ffmpeg_frame.lo] Error 1


Under the ffmpeg-php-0.6.0 directory modify the file: ffmpeg_frame.c with nano or vi editor and replace every instance of PIX_FMT_RGBA32 with PIX_FMT_RGB32

# nano ffmpeg_frame.c
# Search for PIX_FMT_RGBA32 and replace it with PIX_FMT_RGB32
# Exit from the editor

Then run the following commands:

# cd /usr/local/src/ffmpeg-php-0.6.0
# cp -aP ffmpeg_frame.loT ffmpeg_frame.lo
# make clean
# ./configure
#   make
#   make install

This should fix the errors given above. Finally add the ffmpeg.so extension in php.ini and check phpinfo for the server you should see ffmpeg listed.