This protection will log all Spoofed Packets, Source Routed Packets, and Redirect Packets to your log files.

            [root@deep] /# for f in /proc/sys/net/ipv4/conf/*/log_martians; do
            > echo 1 > $f
            > done
            

            [root@deep] /#
            

Add the above commands to the /etc/rc.d/rc.local script file and you'll not have to type it again the next time you reboot your system.

Edit the /etc/sysctl.conf file and add the following line:

            # Log Spoofed Packets, Source Routed Packets, Redirect Packets
            net.ipv4.conf.all.log_martians = 1
            

You must restart your network for the change to take effect. The command to manually restart the network is the following:

            [root@deep] /# /etc/rc.d/init.d/network restart
            Setting network parameters	     [  OK  ]
            Bringing up interface lo	     [  OK  ]
            Bringing up interface eth0	     [  OK  ]
            Bringing up interface eth1	     [  OK  ]