NAT-Network Address Translation is used to communicate from one network to other network with different sub-net.So your Linux box will act as a gateway and will allow to communicate between two different networks.

tcpdump is a common command line packet analyzer.It allows the user to intercept and display TCP/IP and other packets being transmitted or received over a network to which the computer is attached.tcpdump works on most UNIX like operating systems. USAGE: #tcpdump                               –Display standard tcpdump output #tcpdump -v ,-vv, -vvv           [...]

Let see how to install and configure mrtg with this article. Required packages mrtg-2.10.15-1.i386.rpm net-snmp net-snmp-utils Prerequisite: snmp should be configured and running Change the permissions of the directory #chmod 777 /var/www/mrtg Generate a configuration file #cfgmaker –output=/etc/mrtg/mrtg.cfg -ifref=ip –global “workdir: /var/www/mrtg” –global ‘options[_]: growright,bits’ user@192.168.0.10 Edit the configuration file and make the necessary changes. [...]

STEP 1: (The settings for the initial IP address) $ cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 BOOTPROTO=static BROADCAST=192.168.99.255 IPADDR=192.168.1.155 NETMASK=255.255.252.0 NETWORK=192.168.1.0 ONBOOT=yes STEP 2 (2nd IP address: ) $cat /etc/sysconfig/network-scripts/ifcfg-eth0:1 DEVICE=eth0:1 BOOTPROTO=static BROADCAST=192.168.99.255 IPADDR=192.168.1.182 NETMASK=255.255.252.0 NETWORK=192.168.1.0 ONBOOT=yes Note:In STEP 1 the filename is “ifcfg-eth0″, whereas in STEP 2 it’s “ifcfg-eth0:1″ and also not the matching entries for “DEVICE=…”. [...]