Thanks, Paul. FWIW, B is strictly a UA, not a part-time proxy. The implementors of A have traced the problem to P's attachment of a value to the ;lr parameter in the RR:
Record-Route: <sip:xxx.xxx.xxx.xxx:5060;lr=on> They say that's the cause of the breakage. This view is certainly supported by RFC 3261; its grammar clearly states that this is a value-less parameter. However--and I'm sure this has been beaten to death over the years--there are some broken UAs out there that actually _do_ expect an lr= value, to such an extent that Kamailio/OpenSIPS (P is Kamailio in this case) provide a configuration directive to enable the assignment of an lr parameter value in inserted RR headers: http://kamailio.org/docs/modules/4.3.x/modules/rr.html#idm20528 Our implementation of P had this enabled. Seems one can't win. There's got to be a reason this option came about. However, it's been around for a long time, and may date back to the mid 2000s... Any empirical knowledge of whether there remain UAs out there nowadays that don't properly support bareword 'lr'? -- Alex Balashov | Principal | Evariste Systems LLC 303 Perimeter Center North, Suite 300 Atlanta, GA 30346 United States Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct) Web: http://www.evaristesys.com/, http://www.csrpswitch.com/ Sent from my BlackBerry. _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
