How to change MTU settings:

The ifconfig command can be used to change the MTU on the fly. The command is

ifconfig eth0 mtu 1492

for LAN interface.

To make this change permanent, the following line should be added/modified in the file

/etc/sysconfig/network-scripts/ifcfg-eth0

MTU=1492

This will take effect after reboot.

Run ifconfig eth0, the MTU shown will be 1492.

Change eth0 to eth1 or eth2 as necessary.