[asterisk-bugs] [Asterisk 0018633]: asterisk does not respond with ACK on retransmission of 200 OK after it sent ACK

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
====================================================================== 
https://issues.asterisk.org/view.php?id=18633 
====================================================================== 
Reported By:                rrevels
Assigned To:                
====================================================================== 
Project:                    Asterisk
Issue ID:                   18633
Category:                   Channels/chan_sip/General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     feedback
Asterisk Version:           Older 1.6.2 - please test a newer version 
JIRA:                        
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
====================================================================== 
Date Submitted:             2011-01-17 09:31 CST
Last Modified:              2011-02-16 20:07 CST
====================================================================== 
Summary:                    asterisk does not respond with ACK on retransmission
of 200 OK after it sent ACK
Description: 
Upstream blocking causes the first ACK to be dropped before hitting
destination.  Retransmitted 200s show up in network trace on Asterisk
server but no ACK response is ever generated
====================================================================== 

---------------------------------------------------------------------- 
 (0132066) rrevels (reporter) - 2011-02-16 20:07
 https://issues.asterisk.org/view.php?id=18633#c132066 
---------------------------------------------------------------------- 
I have tried revision 1.6.2.9 and 1.6.2.16.1 and both have the problem. I
did not have the problem when jumping up to the 1.8 branch but there were
too many other config changes needed to make that worth doing for my
production servers right now.

I found that I could resolve the problem by forcing a send ack at the
bottom of __sip_ack when the function was called with a response to an
INVITE and no transaction was matched in the function.

I don't have anything behind NAT upstream.  The first 200 does indeed get
a proper ACK and if that makes it all the way through the network the call
sets up fine. The problem only occurs when the 200 has to be retransmitted
due to the first ACK getting lost. The retransmitted 200s don't get ACKed. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2011-02-16 20:07 rrevels        Note Added: 0132066                          
======================================================================