MTU means maximum transmission unit. The default value is 1500 for Ethernet, which is also the standard for the Internet. If your application or network requires a different MTU size, you can set the MTU size by running the following commands.

# Edit ifcfg-eth0
vi /etc/sysconfig/network-scripts/ifcfg-eth0

#Add MTU, settings:
MTU="1460"

# Save and close the file. Restart networking:
service network restart