Disabling icmp redirect messages – Brocade BigIron RX Series Configuration Guide User Manual

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BigIron RX Series Configuration Guide

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Configuring forwarding parameters

7

NOTE

Disabling an ICMP unreachable message type does not change the device’s ability to forward
packets. Disabling ICMP unreachable messages prevents the device from generating or forwarding
the unreachable messages.

To disable all ICMP Unreachable messages, enter the following command.

BigIron RX(config)# no ip icmp unreachable

Syntax: [no] ip icmp unreachable [network | host | protocol | administration |

fragmentation-needed | port | source-route-fail]

If you enter the command without specifying a message type (as in the example above), all
types of ICMP Unreachable messages listed above are disabled. If you want to disable only
specific types of ICMP Unreachable messages, you can specify the message type. To disable
more than one type of ICMP message, enter the no ip icmp unreachable command for each
messages type.

The network parameter disables ICMP Network Unreachable messages.

The host parameter disables ICMP Host Unreachable messages.

The protocol parameter disables ICMP Protocol Unreachable messages.

The administration parameter disables ICMP Unreachable (caused by Administration action)
messages.

The fragmentation-needed parameter disables ICMP Fragmentation-Needed But
Don’t-Fragment Bit Set messages.

The port parameter disables ICMP Port Unreachable messages.

The source-route-fail parameter disables ICMP Unreachable (caused by Source-Route-Failure)
messages.

To disable ICMP Host Unreachable messages and ICMP Network Unreachable messages but leave
the other types of ICMP Unreachable messages enabled, enter the following commands instead of
the command shown above.

BigIron RX(config)# no ip icmp unreachable host

BigIron RX(config)# no ip icmp unreachable network

If you have disabled all ICMP Unreachable message types but you want to re-enable certain types,
you can do so entering commands such as the following.

BigIron RX(config)# ip icmp unreachable host

BigIron RX(config)# ip icmp unreachable network

The commands shown above re-enable ICMP Unreachable Host messages and ICMP Network
Unreachable messages.

Disabling ICMP redirect messages

You can disable or re-enable ICMP redirect messages. By default, the device sends an ICMP
redirect message to the source of a misdirected packet in addition to forwarding the packet to the
appropriate router. You can disable ICMP redirect messages on a global basis or on an individual
port basis.

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