Service Manual

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. On the device, the time between ARP resend is
configurable. This timer is an exponential backoff timer. Over the specified period, the time between ARP
requests increases. This time increase reduces the potential for the system to slow down while waiting
for a multitude of ARP responses.
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.
IPv4 Routing
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