Deployment Guide

Usage Information When a UDP broadcast packet is ooded out of an interface, and the outgoing interface is congured using this
command, the outgoing packet’s IP destination address is replaced with the congured broadcast address.
Related Commands
debug ip udp-helper — enables debug and displays the debug information on a console.
show ip udp-helper — displays the congured UDP helpers on all interfaces.
ip udp-helper udp-port
Enable the UDP broadcast feature on an interface either for all UDP ports or a specied list of UDP ports.
Syntax
ip udp-helper udp-port [udp-port-list]
To disable the UDP broadcast on a port, use the no ip udp-helper udp-port [udp-port-list]
command.
Parameters
udp-port-list (OPTIONAL) Enter up to 16 comma-separated UDP port numbers.
NOTE: If you do not use this option, all UDP ports are considered by default.
Defaults none
Command Modes INTERFACE (cong-if)
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information
If you congure the ip helper-address command and ip udp-helper udp-port command, the
behavior is that the UDP broadcast trac with port numbers 67/68 is unicast relayed to the DHCP server per the
ip helper-address conguration. This occurs regardless if the ip udp-helper udp-port command
contains port numbers 67/68 or not.
If you only congure the ip udp-helper udp-port command, all the UDP broadcast trac is ooded,
including ports 67/68 trac if those ports are part of the udp-port-list.
Related Commands
ip helper-address — congures the destination broadcast or host address for the DHCP server.
debug ip udp-helper — enables debug and displays the debug information on a console.
show ip udp-helper — displays the congured UDP helpers on all interfaces.
show ip udp-helper
Display the congured UDP helpers on all interfaces.
Syntax
show ip udp-helper
Defaults none
Interfaces 563