Reference Guide

ip netdirbcast
This command enables the forwarding of network-directed broadcasts on an interface or range of
interfaces. When enabled, network directed broadcasts are forwarded. When disabled they are
dropped.
Default disabled
Format ip netdirbcast
Mode Interface Config
no ip netdirbcast
This command disables the forwarding of network-directed broadcasts. When disabled, network
directed broadcasts are dropped.
Format no ip netdirbcast
Mode Interface Config
ip mtu
This command sets the IP Maximum Transmission Unit (MTU) on a routing interface or range of
interfaces. The IP MTU is the size of the largest IP packet that can be transmitted on the interface
without fragmentation. Forwarded packets are dropped if they exceed the IP MTU of the outgoing
interface.
Packets originated on the router, such as OSPF (Open Shortest Path First) packets, may be fragmented
by the IP stack.
OSPF advertises the IP MTU in the Database Description packets it sends to its neighbors during
database exchange. If two OSPF neighbors advertise dierent IP MTUs, they will not form an adjacency.
(unless OSPF has been instructed to ignore dierences in IP MTU with the ip ospf mtu-ignore
command.)
Note
The IP MTU size refers to the maximum size of the IP packet (IP Header + IP payload). It does
not include any extra bytes that may be required for Layer-2 headers. To receive and process
packets, the Ethernet MTU (see mtu on page 279) must take into account the size of the
Ethernet header.
For more information about the 200 Series IP MTU, see the Maximum Transmission Unit in 200 Series
Application Note (document number 200 Series-AN40X-R).
Default
1500 bytes
Format ip mtu 68-12270
Mode Interface Config
Routing Commands
ExtremeSwitching 200 Series: Command Reference Guide for version 01 .02.04.0007 512