Deployment Guide

Table Of Contents
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 EMC 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
To view the interfaces and ports on which you enabled UDP helper, use the show ip udp-helper command from EXEC
Privilege mode.
DellEMC#show ip udp-helper
--------------------------------------------------
Port UDP port list
--------------------------------------------------
te 1/1/1 1000
Configurations Using UDP Helper
When you enable UDP helper and the destination IP address of an incoming packet is a broadcast address, Dell EMC Networking
OS suppresses the destination address of the packet.
The following sections describe various configurations that employ UDP helper to direct broadcasts.
UDP Helper with Broadcast-All Addresses
UDP Helper with Subnet Broadcast Addresses
UDP Helper with Configured Broadcast Addresses
UDP Helper with No Configured Broadcast Addresses
UDP Helper with Broadcast-All Addresses
When the destination IP address of an incoming packet is the IP broadcast address, Dell EMC Networking OS rewrites the
address to match the configured broadcast address.
In the following illustration:
1. Packet 1 is dropped at ingress if you did not configure UDP helper address.
IPv4 Routing
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