We are also facing this issue intermittently. We looked at the Wireshark packet traces as well but they don't give any specific pointers. I did notice DNS SRV queries for IP Address which seemed odd, so I pointed out that.
Regarding DNS settings, we removed the DNS Server entries from IP settings of Network Adapter on Client machine and left both Primary/Secondary DNS servers blank.
I have logged this in Issue Tracker and has been assigned Issue # 832.
As you mentioned that this is a known issue; kindly provide some more information on the same. Has this been observed only while using IP Addresses? Or while running Sip Comm in a network with no DNS entries? Any other observations which may help us find a temporary workaround to avoid it while this issue is troubleshoot-ed and fixed.
Also while looking at Team & Contributors page, I noticed that Alan Kelly had submitted a patch that avoids DNS queries by the SIP package when using raw IP addresses. Would incorporating that patch would help here? How can I find out which file(s) were modified for that patch?
Thanks for your support.
From: Emil Ivov [mailto:firstname.lastname@example.org]
Sent: Thursday, June 24, 2010 8:12 PM
Cc: Apurv Agnihotri
Subject: Re: [sip-comm-dev] DNS LookUp Issue
We've been meaning to address this for a while now but had trouble
pinning down the exact circumstances in which the problem appears. It's
good to know that you seem to have them.
Could you please log an issue in our tracker? In addition to what's in
the mail you may also want to mention how the DNS settings look on the
machine where the problem occurs: is there no DNS specified or is it an
address that's not reachable from your location.
I believe Damian was working on this before and he's away atm but he'll
probably have a look in a couple of weeks (which is why the issue entry
would be a necessary reminder ).
Thanks for the report!
На 24.06.10 14:59, Apurv Agnihotri написа:
We are using SIP
with a locally installed SIP server in our Intranet and it works
perfectly fine for Third-party Call Control scenario orchestrated by a
However, when we perform the same setup in a isolated Lab network with
no DNS server and using Statically configured IPs on SIP server and
Client machines, we are facing a strange behavior with Sip Communicator.
It generates a 100 Trying message immediately on incoming INVITE, but
notifies user of incoming call (as well as generates 180 Ringing) only
after a long delay of 6-10 seconds. Also once user accepts the call (for
which 200 OK is generated instantaneously), the ringing continues for
many-many seconds because the Ack sent back by SIP server is not
processed right away.
We are not able to understand the reason for such a behavior. Noticed
that Sip Server is sending Notify of Sip-Message-Summary to Sip
Communicator after initial REGISTER which seems to be forcing Sip
Communicator to send out multiple DNS SRV queries for
_sip._udp.<ip-address>. Can this be hogging the threads of Sip
Communicator and reason for the delay? Also*, as we are using just IP
Address in isolated Lab network; why is DNS lookup done at all?*