HP ProCurve 7102dl Reference Manual page 801

SROS Command Line Interface Reference Guide
ip helper-address <address>
Use the ip helper-address command to configure SROS to forward User Datagram Protocol (UDP)
broadcast packets received on the interface. Use the no form of this command to disable forwarding
packets.
Note
The ip helper command must be used in conjunction with the ip forward-protocol command
to configure SROS to forward UDP broadcast packets. See ip forward-protocol udp <port
number> on page 412 for more information.
Syntax Description
< address>
Default Values
By default, broadcast UDP packets are not forwarded.
Functional Notes
When used in conjunction with the ip forward-protocol command, the ip helper-address feature allows
you to customize which broadcast packets are forwarded.
To implement the helper address feature, assign a helper-address(es) (specifying the device that needs to
receive the broadcast traffic) to the interface closest to the host that transmits the broadcast packets.
When broadcast packets (of the specified type forwarded using the ip forward-protocol command) are
received on the interface, they will be forwarded to the device that needs the information.
Only packets meeting the following criteria are considered eligible by the ip helper-address feature:
1. The packet IP protocol is User Datagram Protocol (UDP).
2. Any UDP port specified using the ip forward-protocol command.
3. The media access control (MAC) address of the frame is an all-ones broadcast address (ffff.ffff.ffff).
4. The destination IP address is broadcast defined by all ones (255.255.255.255) or a subnet broadcast
(for example, 192.33.4.251 for the 192.33.4.248/30 subnet).
Usage Examples
The following example forwards all DNS broadcast traffic to the DNS server with IP address 192.168.5.99:
ProCurve(config)#iinterface bvi 1
ProCurve(config)#ip forward-protocol udp domain
ProCurve(config)#interface bvi 1
ProCurve(config-bvi 1)#ip helper-address 192.168.5.99
5991-2114
Specifies the destination IP address (in dotted decimal notation) for the forwarded
UDP packets.
© Copyright 2007 Hewlett-Packard Development Company, L.P.
BVI Interface Config Command Set
799