DELL S6000-ON User Manual

ICMP

For diagnostics, the internet control message protocol (ICMP) provides routing information to end 
stations by choosing the best route (ICMP redirect messages) or determining if a router is reachable 
(ICMP Echo or Echo Reply).
ICMP error messages inform the router of problems in a particular packet. These messages are sent only 
on unicast traffic.

Configuration Tasks for ICMP

The following lists the configuration tasks for ICMP.
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For a complete listing of all commands related to ICMP, refer to the Dell Networking OS Command Line 
Reference Guide.

Enabling ICMP Unreachable Messages

By default, ICMP unreachable messages are disabled.

When enabled, ICMP unreachable messages are created and sent out all interfaces.
To disable and re-enable ICMP unreachable messages, use the following commands.

• To disable ICMP unreachable messages.

INTERFACE mode

no ip unreachable

• Set FTOS to create and send ICMP unreachable messages on the interface.

INTERFACE mode

ip unreachable

To view if ICMP unreachable messages are sent on the interface, use the show config command in 
INTERFACE mode. If it is not listed in the show config command output, it is enabled. Only non-default 
information is displayed in the show config command output.

UDP Helper

User datagram protocol (UDP) helper allows you to direct the forwarding IP/UDP broadcast traffic by 
creating special broadcast addresses and rewriting the destination IP address of packets to match those 
addresses.

Configure UDP Helper

Configuring Dell Networking OS to direct UDP broadcast is a two-step process:

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IPv4 Routing