Users 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 Dell Networking OS 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
To configure Dell Networking OS to direct UDP broadcast, enable UDP helper and specify the UDP ports for which traffic is forwarded.
See Enabling UDP Helper
Important Points to Remember
• The existing ip directed broadcast command is rendered meaningless if you enable UDP helper on the same interface.
• The broadcast traffic 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 traffic with port number 67 or 68 are unicast to the dynamic host configuration protocol (DHCP) server per the ip
helper-address configuration whether or not the UDP port list contains those ports.
○ If the UDP port list contains ports 67 or 68, UDP broadcast traffic is forwarded on those ports.
Enabling UDP Helper
To enable UDP helper, use the following command.
• Enable UPD helper.
ip udp-helper udp-ports
Dell(conf-if-te-1/1)#ip udp-helper udp-port 1000
Dell(conf-if-te-1/1)#show config
!
interface TenGigabitEthernet 1/1
ip address 2.1.1.1/24
ip udp-helper udp-port 1000
no shutdown
To view the interfaces and ports on which you enabled UDP helper, use the show ip udp-helper command from EXEC Privilege
mode.
Dell#show ip udp-helper
--------------------------------------------------
Port UDP port list
IPv4 Routing
369