Now I am thinking that the Fragmented IP may be a red herring since n the old version it's also happening but only once. Then the softphone acknowledges it and that's the end of it. Something in the OK message from the current master prevents the softphone from acknowledging the OK message. I could not find significant differences in the OK message with the old version that works. The only difference seems to be Min-SE: 120 header in the old version which is missing from the new one.

This is happening with at least two completely different softphone, so I can't blame the phones :-) It's 100% reproducible.

What else can I do to debug this?

Any help would be greatly appreciated!

On Fri, May 23, 2014 at 10:10 PM, Oleg Stolyar <olegstolyar@gmail.com> wrote:

Hi guys,

I upgraded to the master (and it's also happening in 1.4.4). I have some very long SIP addresses in my messages. It used to work fine on the master from August 2013. However, now when FS sends back the OK message, to invites with very long destination numbers, the originator softphone cannot receive it. This is only happening with UDP. TCP works fine.

Here is a snapshot of wireshark for the master
https://www.dropbox.com/s/0y0m4f4t4cgnwu0/Current%20Master.PNG

And here is the snapshot of the same OK messages for the August 2013 FS that works
https://www.dropbox.com/s/7wpsyw4r2skifpb/August%202013%20Version.PNG

Any ideas how to fix this? Is this a known issue?