[Users] thought exercise

[Mark Kent]

I wonder if anyone on this list is open to a thought exercise?
I'm trying to put together a cogent message about this, 
but in the meantime:

I've got a situation where my openser box seems to route stuff to itself
and it loops around and around until I get the classic "Too Many Hops" error.

This seems to happen most often on BYE, although I've seen an ACK do it too.
Here is a small ngrep snippet, after

PHONE has called OPENSER-ONE who statelessly relays to OPENSER-TWO
who t_relays to PSTNGW, and then the pstn user hangs-up:

 U  23:03:53.254382 PSTNGW:5060 -> OPENSER-TWO:5060
 BYE sip:JoeUser at OPENSER-ONE.example.com:5060;user=phone SIP/2.0
 Call-ID: callid at PHONE
 From: <sip:18005551212 at OPENSER-TWO.example.com:5060>;tag=26674
 To: "Joe User" <sip:JoeUser at OPENSER-ONE.example.com>;tag=thetag
 Content-Length: 0
 CSeq: 1 BYE
 Via: SIP/2.0/UDP PSTNGW:5060;branch=thebranch
 Route: <sip:JoeUser at OPENSER-ONE:5060>
 Max-Forwards: 70

 #
 U  23:03:53.255013 OPENSER-TWO:5060 -> OPENSER-ONE:5060
 BYE sip:JoeUser at OPENSER-ONE:5060 SIP/2.0
 Record-Route: <sip:JoeUser at OPENSER-TWO;lr=on;ftag=26674>
 Call-ID: callid at PHONE
 From: <sip:18005551212 at OPENSER-TWO.example.com:5060>;tag=26674
 To: "Joe User" <sip:JoeUser at OPENSER-ONE.example.com>;tag=thetag
 Content-Length: 0
 CSeq: 1 BYE
 Via: SIP/2.0/UDP OPENSER-TWO;branch=otherbranch.0
 Via: SIP/2.0/UDP PSTNGW:5060;branch=thebranch
 Max-Forwards: 69
 Route: <sip:JoeUser at OPENSER-ONE.example.com:5060;user=phone>

Right here OPENSER-ONE freaks out, and the delay causes
OPENSER-TWO to re-transmit:

 #
 U  23:03:53.611227 OPENSER-TWO:5060 -> OPENSER-ONE:5060
 BYE sip:JoeUser at OPENSER-ONE:5060 SIP/2.0
 Record-Route: <sip:JoeUser at OPENSER-TWO;lr=on;ftag=26674>
 Call-ID: callid at PHONE
 From: <sip:18005551212 at OPENSER-TWO.example.com:5060>;tag=26674
 To: "Joe User" <sip:JoeUser at OPENSER-ONE.example.com>;tag=thetag
 Content-Length: 0
 CSeq: 1 BYE
 Via: SIP/2.0/UDP OPENSER-TWO;branch=otherbranch.0
 Via: SIP/2.0/UDP PSTNGW:5060;branch=thebranch
 Max-Forwards: 69
 Route: <sip:JoeUser at OPENSER-ONE.example.com:5060;user=phone>

OK, so who on this list is good enough to be able to suggest plausible
theories about what my openser.cfg flaw is?  If you don't want to
speculate openly on the list then please send me a direct email.

Thanks,
-mark