Persistently change the MTU of an network interface (Red Hat)
|Red Hat-based distributions|
To persistently change the MTU of a network interface on a Red Hat-based system
Edit the configuration script for the relevant interface in
/etc/sysconfig/network-scripts/. If named directly after the interface
eth0 then this would be called
ifcfg-eth0, however other names are possible (including
ifcfg-Auto_eth0 if using the Gnome Network Manager). If no configuration script exists then you will need to create one.
Add a line to specify the MTU, for example:
DEVICE=eth0 BOOTPROTO=static ONBOOT=yes IPADDR=192.168.0.2 NETMASK=255.255.255.0 MTU=9000
Unlike the corresponding method for Debian-based systems, it is possible to set the MTU of interfaces that use DHCP:
DEVICE=eth0 BOOTPROTO=dhcp HWADDR=02:00:00:00:00:00 ONBOOT=yes MTU=9000
It is permissible for the values given in this file to be single- or double-quoted.
The new MTU can be activated by taking the interface down using
ifdown then bringing it back up using
ifdown eth0 ifup eth0
Alternatively you could reboot the machine.
An error of the form:
Error: argument "x" is wrong: invalid "mtu" value
indicates that the specified MTU could not be interpreted as an integer.
The following configuration programs have the ability to change the MTU of a network interface:
|Centos 5.5||system-config-network||System ⇒ Administration ⇒ Network|
|Fedora 14||nm-connection-editor||System ⇒ Preferences ⇒ Network Connections|
|OpenSUSE 11.3||yast2||Computer ⇒ YaST|
These interoperate with the configuration script described above, so it should be possible to switch between manual and assisted configuration with caution.