Command Line Reference Guide

ip helper-address
Specify the address of a DHCP server so that DHCP broadcast messages can be forwarded when the
DHCP server is not on the same subnet as the client.
Z9500
Syntax
ip helper-address ip-address
To remove a DHCP server address, use the no ip helper-address command.
Parameters
ip-address Enter an IP address in dotted decimal format (A.B.C.D).
Defaults Not configured.
Command
Modes
INTERFACE
Command
History
This guide is platform-specific. For command information about other platforms,
refer to the relevant Dell Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.2(1.0) Introduced on the Z9500.
9.0.0.0 Added support for IPv6.
8.3.19.0 Introduced on the S4820T.
8.3.11.1 Introduced on the Z9000.
8.3.7.0 Introduced on the S4810.
8.1.1.0 Introduced on the E-Series ExaScale.
7.9.1.0 Introduced VRF on the E-Series.
7.6.1.0 Introduced on the S-Series.
7.5.1.0 Introduced on the C-Series.
6.2.1.1 Introduced on the E-Series.
Usage
Information
You can add multiple DHCP servers by entering the ip helper-address
command multiple times. If multiple servers are defined, an incoming request is
sent simultaneously to all configured servers and the reply is forwarded to the
DHCP client.
The system uses standard DHCP ports, that is UDP ports 67 (server) and 68 (client)
for DHCP relay services. It listens on port 67 and if it receives a broadcast, the
software converts it to unicast, and forwards to it to the DHCP-server with source
port=68 and destination port=67.
820
IPv4 Routing