Name
ip helper-address — interface
Synopsis
ip helper-addressaddress
no ip helper-addressaddress
Configures
IP address to which certain broadcast UDP packets are forwarded
Default
Disabled
Description
This command sets the helper address to
address
. The helper address should be the
address of a host that can answer UDP requests from other hosts. The
router sees these requests broadcast on a LAN interface and forwards
them to the helper address (generally a unicast address) if one is
defined. A helper is particularly useful for DHCP requests; without
some kind of forwarding, DHCP requires you to have a separate server
on every subnet. By itself, this command forwards packets for the
BOOTP (DHCP), DNS, TFTP, TACACS, TIME, and NetBIOS name and datagram
services. The ip
forward-protocol
command can be used to forward
additional UDP services.
Example
To configure interface ethernet0
to have a helper
address:
interface ethernet0 ip address 10.10.1.2 255.255.255.0 ip helper address 10.10.2.5
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