Great. Thanks for the info.

One more question. Since a call can be forwarded to another SIP phone or to a PSTN phone, I need to determine how to route the REFER message.

So would I basically do something like this:

route {

    if (method=='REFER') {

         if (!regeristered("location")) {
                 rewritehostport("xxx.xxx.xxx.xxx"); # IP of the PSTN gateway
         }

         t_relay();
    }
}


Regards,
Paul

On 6/1/05, Marian Dumitru <marian.dumitru@voice-sistem.ro> wrote:
Hi Paul,

Just two comments:

1) the message shouldn't be RURI driven, but ROUTE driven, so it
shouldn't hit location.

2) Refer-to URI shouldn't be used for routing the REFER - this header
will tell to the destination user which user to contact/refer.

Regards,
Marian

Java Rockx wrote:
> Hi All.
>
> I've got a question about handling REFER messages. Below is a REFER
> message that my Grandstream GXP2000 phone generated when I transferred a
> call to another SIP phone on the same SER proxy.
>
> The problem is that SER did a lookup('location') and couldn't find the
> phone number in the subscriber table, so it routed the message to the
> PSTN gateway.
>
> SER should have looked at the Refer-To header to get the actual
> destination of the message.
>
> How can I get SER to handle this message correctly? Should REFER
> messages hit the lookup('location') function in my ser.cfg script?
>
> NOTE: my SER proxy sits behind a Cisco 3600 so the ALG functionality has
> altered the IP. The message shows my SER server as IP address 10.3.0.221
> <http://10.3.0.221>
>
> Regards,
> Paul
>
> U 2005/06/01 14:22:24.073518 66.90.46.29:5060 <http://66.90.46.29:5060>
> -> 10.3.0.221:5060 <http://10.3.0.221:5060 >
> REFER sip:4075552279@66.243.109.99:5060 SIP/2.0.
> Via: SIP/2.0/UDP 172.31.130.139
> <http://172.31.130.139>;branch=z9hG4bK09ff837994d9e898.
> Route: <sip:4075552279@10.3.0.221:5060;nat=yes;ftag=204ed7cd9666ebba;lr>.
> Route: <sip:216.229.127.60:5060 <http://216.229.127.60:5060 >;lr>.
> From: 3212514238 <sip:3212514238@66.243.109.99:5060>;tag=204ed7cd9666ebba.
> To: sip:4075552279@66.236.245.100
> <mailto: sip:4075552279@66.236.245.100>;tag=EB25EC-B85.
> Contact: <sip:3212514238@172.31.130.139
> <mailto: sip:3212514238@172.31.130.139>>.
> Supported: replaces.
> Refer-To: <sip:3212814820@sip.mycompany.com
> <mailto:sip:3212814820@sip.mycompany.com>>.
> Referred-By: <sip:3212514238@172.31.130.139
> <mailto:sip:3212514238@172.31.130.139>>.
> Call-ID: 13195134-3326638548-685571@66.243.109.99
> <mailto:13195134-3326638548-685571@66.243.109.99>.
> CSeq: 51906 REFER.
> User-Agent: Grandstream GXP2000 1.0.1.8 <http://1.0.1.8>.
> Max-Forwards: 70.
> Allow:
> INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDATE,PRACK.
> Content-Length: 0.

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