Administrator Guide
Layer 3 Routing Commands 1539
The command no ip helper-address with no arguments clears all global IP
helper addresses.
When in Virtual Router Configuration mode, this command operates within
the context of the virtual router instance. When in Global Configuration
mode, the command operates on the global router instance.
Virtual Router Configuration mode is only available on the N3000/N4000
switches.
Example
To relay DHCP packets received on any interface to two DHCP servers,
10.1.1.1 and 10.1.2.1, use the following commands:
console#config
console(config)#ip helper-address 10.1.1.1 dhcp
console(config)#ip helper-address 10.1.2.1 dhcp
To relay UDP packets received on any interface for all default ports (see
Table 7-2) to the server at 20.1.1.1, use the following commands:
console#config
console(config)#ip helper-address 20.1.1.1
ip helper-address (interface configuration)
Use the ip helper-address (interface configuration) command to configure
the relay of certain UDP broadcast packets received on a specific interface. To
delete a relay entry on an interface, use the no form of this command.
Syntax
ip helper-address {server-address | discard} [dest-udp-port | dhcp | domain
| isakmp | mobile ip | nameserver | netbios-dgm | netbios-ns | ntp | pim-
auto-rp | rip | tacacs | tftp | time]
no ip helper-address [
server-address
| discard] [
dest-udp-port
| dhcp |
domain | isakmp | mobile-ip | nameserver | netbios-dgm | netbios-ns | ntp
| pim-auto-rp | rip | tacacs | tftp | time]
•
server-address
— The IPv4 unicast or directed broadcast address to which
relayed UDP broadcast packets are sent. The server address cannot be an
IP address configured on any interface of the local router.
2CSNXXX_SWUM204.book Page 1539 Monday, January 25, 2016 1:25 PM