As we know the kerberos authentication method is the most secure network authentication method ever build. In normal method the password is sent accross the network, which is vulnerable but in kerberos method no password is sent accross the network.
The Steps included in kerberos authentication
users enters his user name and …

We usally configure the proxy server to share the internet over the internal network, users inside the network can access the internet through the proxy server. All the logs of the internet usage are stored in proxy server logs files, but there is a problem in this condition. we cannot …

In some areas they are different networks in the same building, we need a DHCP server to provide Ip address for the computers in this different networks. It is possible to configure DHCP server with multiple range of ip address.
Configuration  Example

In the working example configuration shown below, the DHCP …

In mail service we can use alias function to forward the mails  coming to a mail id to a another mail address, In some cases the destination mail address may be one for more. Basically they are 5 different types of alias methods which can be used to forward the …

In some cases we can seen that there is attack coming to our server from a particular range of ip, in that case we need to block only that range not the full range. In that situtation we can use iptables
Example: If attack is coming from 202.10.100.20 to range of …

Hotlinking is the use of a linked object, often an image, from one site into a web page belonging to a second site. The second site is said to have an inline link to the site where the object is located.
It is always recommended to enable hotlinking of images, else …

Kernel 
 It makes sure that all processes in the system works fine
Rebuilding

It is done to optimize the kernel to suit our requirements as well as make it more secure from internet attacks
 Steps

1. Determining the current hardware 
 This is required during configuration process to enable hardwares that our new kernel has to support.
Commands …

To find the processor type and details
Get the Processor details:

cat /proc/cpuinfo

Find whether the processor is 32 or 64 bit:

 getconf LONG_BIT

Find the architecture:

uname -i

 Ping Requests use ICMP protocols. This is enabled/disabled using sysctl values.
To Disable Ping:
 
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
 
To Enable Ping:
 
echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all

 Scenario
To log into “Server A” from “Server B” without using passwords. Users for both the server will be “root”
Process

 Login to “Server B” as root user and generate key for the root user. No need to enter any passphrase while generating this key.

ssh-keygen -t rsa
 
Once the key is generated, copy the …