Icmp; Configuration Tasks For Icmp; Enabling Icmp Unreachable Messages; Udp Helper - Dell S4820T Configuration 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.
•

Enabling ICMP Unreachable Messages

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:
IPv4 Routing
493