Users Guide

UDP Helper
User datagram protocol (UDP) helper allows you to direct the forwarding IP/UDP broadcast trac by creating special broadcast
addresses and rewriting the destination IP address of packets to match those addresses.
Congure UDP Helper
Conguring Dell Networking OS to direct UDP broadcast is a two-step process:
1. Enable UDP helper and specify the UDP ports for which trac is forwarded. Refer to Enabling UDP Helper.
2. Congure a broadcast address on interfaces that will receive UDP broadcast trac. Refer to Conguring 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 trac 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 trac with port number 67 or 68 are unicast to the dynamic host conguration protocol (DHCP) server per
the ip helper-address conguration whether or not the UDP port list contains those ports.
– If the UDP port list contains ports 67 or 68, UDP broadcast trac is forwarded on those ports.
Enabling UDP Helper
To enable UDP helper, use the following command.
• Enable UPD helper.
ip udp-helper udp-ports
Example of Enabling UDP Helper and Using the UDP Helper show Command
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
--------------------------------------------------
te 1/1 1000
Conguring a Broadcast Address
To congure a broadcast address, use the following command.
• Congure a broadcast address on an interface.
ip udp-broadcast-address
Examples of Conguring and Viewing a Broadcast Address
Dell(conf-if-vl-100)#ip udp-broadcast-address 1.1.255.255
Dell(conf-if-vl-100)#show config
IPv4 Routing
417