CLI Reference Guide
IP Helper/DHCP Relay Commands 1037
console(config)#interface vlan 10
console(config-if-vlan10)#ip dhcp relay information option-insert
ip helper-address (global configuration)
Use the ip helper-address (global configuration) command to configure the
relay of certain UDP broadcast packets received on any interface. To delete an
IP helper entry, use the no form of this command.
Syntax
ip helper-address
server-address
[
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
] [
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.
•
dest-udp-port
— A destination UDP port number from 0 to 65535.
•
port-name
— The destination UDP port may be optionally specified by its
name. Whether a port is specified by its number or its name has no effect
on behavior. The names recognized are as follows:
dhcp
(port 67),
domain
(port 53),
isakmp
(port 500),
mobile-ip
(port 434),
nameserver
(port 42),
netbios-dgm
(port 138),
netbios-ns
(port 137),
ntp
(port 123),
pim-auto-
rp
(port 496),
rip
(port 520),
tacacs
(port 49),
tftp
(port 69), and
time
(port 37). Other ports must be specified by number.
Default Configuration
No helper addresses are configured.
Command Mode
Global Configuration mode.
2CSNXXX_SWUM200.book Page 1037 Tuesday, December 10, 2013 1:22 PM