Administrator Guide

Version Description
7.5.1.0 Introduced on the C-Series.
pre-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.
Dell Networking OS 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.
The server replies with source port=67, destination port=67 and Dell Networking OS forwards to the
client with source port=67, destination port=68.
ip helper-address hop-count disable
Disable the hop-count increment for the DHCP relay agent.
Z9000
Syntax
ip helper-address hop-count disable
To re-enable the hop-count increment, use the no ip helper-address hop-count disable
command.
Defaults Enabled; the hops field in the DHCP message header is incremented by default.
Command Modes CONFIGURATION
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
9.7(0.0) Introduced on the S6000-ON.
9.0.2.0 Introduced on the S6000.
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.
7.6.1.0 Introduced on the S-Series.
7.5.1.0 Introduced on the C-Series.
6.3.1.0 Introduced for the E-Series.
Usage
Information
This command disables the incrementing of the hops field when boot requests are relayed to a DHCP
server through Dell Networking OS. If the incoming boot request already has a non-zero hops field, the
message is relayed with the same value for hops. However, the message is discarded if the hops field
exceeds 16, to comply with the relay agent behavior specified in RFC 1542.
Related
Commands
ip helper-address — specifies the destination broadcast or host address for DHCP server requests.
show running-config — displays the current configuration and changes from the default values.
594 IPv4 Routing