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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