You could do this with a custom template. Here is quick lesson on custom templates. You should probably read the section on custom templates first at
http://www.e-smith.org/custom/Create the following file using pico:
# pico /etc/e-smith/templates-custom/etc/sysconfig/network-scripts/ifcfg-eth0/10mtuset
Place the following line in it and save:
MTU=1492
Do the same for eth1:
# pico /etc/e-smith/templates-custom/etc/sysconfig/network-scripts/ifcfg-eth1/10mtuset
Expand the templates:
/sbin/e-smith/expand-template /etc/sysconfig/network-scripts/ifcfg-eth0
/sbin/e-smith/expand-template /etc/sysconfig/network-scripts/ifcfg-eth1
Restart network:
/etc/rc.d/rc7.d/S10network restart
Good Luck,
Paul