Ip mtu – Dell PowerEdge M805 User Manual

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IP Routing Commands

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Syntax

ip address ip-address {subnet-mask | prefix-length} [secondary]

no ip address ip-address {subnet-mask | prefix-length} [secondary]

ip-address—IP address of the interface.

subnet-mask—Subnet mask of the interface

prefix-length—Length of the prefix. Must be preceded by a forward slash (/). (Range: 1-30
bits)

secondary—Indicates the IP address is a secondary address.

Default Configuration

This command has no default configuration.

Command Mode

Interface Configuration (VLAN, Loopback) mode

User Guidelines

This command also implicitly enables the interface for routing (i.e. as if the user had issued
the ‘routing’ interface command).

Example

The following example defines the IP address and subnet mask for VLAN 15.

console(config)#interface vlan 15

console(config-if-vlan15)#ip address 192.168.10.10 255.255.255.0

ip mtu

Use the ip mtu command in Interface Configuration mode to set the IP Maximum Transmission
Unit (MTU) on a routing interface. The IP MTU is the size of the largest IP packet that can be
transmitted on the interface without fragmentation. Use the no form of the command to return
the MTU size to the default value.

Software currently does not fragment IP packets. Packets forwarded in hardware ignore the IP
MTU. Packets forwarded in software are dropped if they exceed the IP MTU of the outgoing
interface. Packets originated on the router, such as OSPF packets, may be fragmented by the IP
stack. The IP stack uses its default IP MTU and ignores the value set using the ip mtu command.
OSPF advertises the IP MTU in the Database Description packets it sends to its neighbors during
database exchange. If two OSPF neighbors advertise different IP MTUs, they will not form an
adjacency (unless OSPF has been instructed to ignore differences in IP MTU with the ip ospf
mtuignore command).

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