[Serusers] DNS SRV lookup issue

[Zeus Ng]

For that, I don't know. However, I would say SER is doing the right thing on
RR SRV lookup but that's just my opinion.

The purpose of SRV record is to help application finding 
1) IP address 
2) port number
3) priority (weight) of the service

As you have already specified the port number, the RR SRV lookup would
become redundant. What happen if the port number in the RR record is
different to what you specified? There must be a reason to specify the port
number in URI and SER should honour that.


Zeus


> -----Original Message-----
> From: Chetan Gandhi 
> Sent: Friday, 25 February 2005 5:44 AM
> To: serusers at lists.iptel.org
> Cc: Zeus Ng
> Subject: Re: [Serusers] DNS SRV lookup issue
> 
> 
> Thanks Zeus.
> 
> The problem is solved. In the Contact address I had the port 
> well i.e. user at testdomain.com:5060. Once I removed the port, 
> the SER did do SRV lookup.
> 
> Just to learn from it, do you if this a SIP/SRV protocol 
> nuance or a SER implementation issue ?
> 
> thanks,
> Chetan
> 
> 
> On Thu, 24 Feb 2005 20:04:03 +1100, Zeus Ng 
> <zeus.ng at isquare.com.au> wrote:
> > Are you absolutely sure the contact address is stored as 
> > user at testdomain.com and not user at 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 at testdomain.com, with no port 
> > specified. If the URI does have the port included like 
> > sip:user at 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 at lists.iptel.org 
> [mailto:serusers-bounces at lists.iptel.org] 
> > > On Behalf Of Gandhi, Chetan
> > > Sent: Wednesday, 23 February 2005 9:15 AM
> > > To: serusers at 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 at testdomain.com
> > >
> > > SIP UA2 registers with SER (testdomain.com) with contact address 
> > > user at testdomain.com
> > >
> > >
> > >
> > > Step 2:
> > >
> > > SIP UA3 calls user at 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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>