Centos 7 MTU configuration
To set your Centos 7 system to use MTU 9000, edit the ifcfg file and specify the following:
MTU=9000
Restart networking via ‘service network restart’
Confirm 9000 MTU by running ‘ip addr’
..
2: enp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast state UP qlen 1000
link/ether 00:25:90:36:0d:e2 brd ff:ff:ff:ff:ff:ff
inet 199.193.209.8/28 brd 199.193.209.15 scope global enp4s0
valid_lft forever preferred_lft forever
inet6 fe80::225:90ff:fe36:de2/64 scope link
valid_lft forever preferred_lft forever
..