Service Manual
Conguration Tasks for ICMP
The following lists the conguration 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 trac by creating special broadcast
addresses and rewriting the destination IP address of packets to match those addresses.
Congure UDP Helper
Conguring Dell Networking OS to direct UDP broadcast is a two-step process:
1. Enable UDP helper and specify the UDP ports for which trac is forwarded. Refer to Enabling UDP Helper.
2. Congure a broadcast address on interfaces that will receive UDP broadcast trac. Refer to Conguring a Broadcast Address.
Important Points to Remember
• The existing ip directed broadcast command is rendered meaningless if you enable UDP helper on the same interface.
• The broadcast trac rate should not exceed 200 packets per second when you enable UDP helper.
• You may specify a maximum of 16 UDP ports.
• UDP helper is compatible with IP helper (ip helper-address):
– UDP broadcast trac with port number 67 or 68 are unicast to the dynamic host conguration protocol (DHCP) server per
the ip helper-address conguration whether or not the UDP port list contains those ports.
– If the UDP port list contains ports 67 or 68, UDP broadcast trac is forwarded on those ports.
Enabling UDP Helper
To enable UDP helper, use the following command.
IPv4 Routing
371










