New subject: [Serusers] DNS SRV lookup issue

24 Feb 2005


      I have some issues with DNS mapping too. I want to have a sip user with
sip:user1@testdomain.com. In my location table, I however stored
sip:user1@machine1.testdomain.com as machine1.testdomain.com maps to the
actual IP address (I have such an entry in /etc/hosts). Hence although a DNS
SRV lookup is performed, it tries to contact
_sip._udp.machine1.testdomain.com, which does not exist (I only have SRV
entry for _sip._udp.testdomain.com). I think I'm missing something, can
somebody tell me where?
Any help will be greatly appreciated.
cheers
Chiang
-----Original Message-----
From: Zeus Ng [mailto:zeus.ng@isquare.com.au]
Sent: 24 February 2005 09:04
To: 'Gandhi, Chetan'
Cc: serusers@lists.iptel.org
Subject: RE: [Serusers] DNS SRV lookup issue
Are you absolutely sure the contact address is stored as user@testdomain.com
and not user@some.ip.address in the location table? I'm sure t_relay() will
do SRV lookup, with one condition. The URI should be in the form
sip:user@testdomain.com, with no port specified. If the URI does have the
port included like sip:user@testdomain.com:5060, then SER will not do SRV
lookup.
Most UAs I saw use IP address in contact header and that means no SRV
lookup. Better check yours with serctl ul show.
You can verify the SRV lookup with the following script.
loadmodule "/usr/local/lib/ser/modules/tm.so"
route{
        rewritehost("stupid.domain");
        t_relay();
}
The ethereal output will show SRV lookup.
Zeus
...
-----Original Message-----
From: serusers-bounces@lists.iptel.org 
[mailto:serusers-bounces@lists.iptel.org] On Behalf Of Gandhi, Chetan
Sent: Wednesday, 23 February 2005 9:15 AM
To: serusers@lists.iptel.org
Subject: [Serusers] DNS SRV lookup issue
Hi All,
I am facing problem to get SER to do a SRV lookup. I have the 
following scenario.
Step 1:
SIP UA1 registers with SER (testdomain.com) with contact 
address user@testdomain.com
SIP UA2 registers with SER (testdomain.com) with contact 
address user@testdomain.com
Step 2:
SIP UA3 calls user@testdomain.com
Problem
I would expect SER to do a DNS SRV lookup on testdomain.com 
and get sip1.testdomain.com and sip2.testdomain.com. 
Unfortunately, SER only does A and AAAA query. (verified via 
ethereal) and does not do SRV lookup. How can I make it do 
SRV lookup ? I am using the default ser.cfg file.
DNS entries
_sip._udp.testdomain.com.                     3600     IN     
    SRV     0          1          5060     sip1.testdomain.com.
_sip._udp.testdomain.com.                     3600     IN     
    SRV     0          1          5060     sip2.testdomain.com.
I am trying to do load balancing but the SRV lookup failure 
has got me stuck. Any pointers would be really appreciated.
Thanks,
Chetan
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