Cisco Cisco IOS Software Release 12.2(15)ZJ

To enable Session Initiation Protocol (SIP) gateways to register E.164 numbers on behalf of analog 
telephone voice ports (FXS), IP phone virtual voice ports (EFXS), and SCCP phones with an external 
SIP proxy or SIP registrar, use the registrar command in SIP user-agent configuration mode. To disable 
registration of E.164 numbers, use the no form of this command.

registrar {{dns: address | ipv4: destination-address} expires seconds [tcp] [secondary]}

no registrar [secondary]

3600 seconds

SIP user-agent configuration

By default, SIP gateways do not generate SIP Register messages. This command enables the gateway to 
register E.164 telephone numbers with primary and secondary external SIP registrars. 

The following is example output for the show running-config command. 

sip-ua 

retry invite 3

retry register 3

timers register 150

registrar ipv4:10.8.17.40 expires 3600 secondary

dns: address 

DNS address of the SIP Registrar server.

ipv4:destination- 
address

IP address of the SIP Registrar server.

expires seconds

Default registration time, in seconds. The range is from 60 to 65535 seconds.

(Optional) Sets transport layer protocol to TCP. UDP is the default.

(Optional) Specifies registration with a secondary SIP proxy or registrar to 
provide redundancy if the primary registrar fails.

12.2(15)ZJ

This command was introduced.