Reference Manual

NAME

seti - set the MTU for a specified inteface.

seti ifn [mtu]

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When invoked with only the ifn argument, seti prints the current NAT32 Maximum Transfer Unit (in decimal) for the specified interface. Argument ifn can also be the value p to denote the Primary Interface.

Argument mtu can specify a non-standard MTU for the specified interface. For some implementations of the PPPoE protocol, an MTU of 1400 should be specified.

The altered settings are not recorded in any netcfg file or in the Windows Registry. To make the settings permanent, the command should be placed in file startup.

The MTU adjusment has the effect that maximum length (1500 byte) packets arriving from a private machine will be fragmented at the IP layer before being sent via the Primary Interface. This should make it unnecessary to change the MTU on all attached machines.

Note that most computers will use Path MTU Discovery to learn of non-standard MTUs on any network on the path to a packet's destination. NAT32 fully supports PMTU Discovery and will respond with an appropriate ICMP packet to notify the sender of the reduced MTU on the PPPoE Interface, again making MTU changes on the attached machines unnecessary.

mtu, netcfg, pppoe, setp