Configuring Arp Retries; Icmp; Configuration Tasks For Icmp; Enabling Icmp Unreachable Messages - Dell Force10 Z9000 Configuration Manual

Whether you enable or disable ARP learning via gratuitous ARP, the system does not look up the target IP. It only updates the ARP
entry for the Layer 3 interface with the source IP of the request.

Configuring ARP Retries

In Dell Networking OS versions prior to 8.3.1.0, the number of ARP retries is set to five and is not configurable. After five retries, Dell
Networking OS backs off for 20 seconds before it sends a new request. Beginning with Dell Networking OS version 8.3.1.0, the
number of ARP retries is configurable.
The default backoff interval remains at 20 seconds.
To set and display ARP retries, use the following commands.
• Set the number of ARP retries.
CONFIGURATION mode
arp retries number
The default is 5.
The range is from 1 to 20.
• Set the exponential timer for resending unresolved ARPs.
CONFIGURATION mode
arp backoff-time
The default is 30.
The range is from 1 to 3600.
• Display all ARP entries learned via gratuitous ARP.
EXEC Privilege mode
show arp retries

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
327
IPv4 Routing