No Vivek, its definitely not NAT. It is 2 IP addresses in DNS server for a hostname.
On Fri, Sep 19, 2014 at 7:50 PM, Vivek Talwar <vivek.tal...@globallogic.com> wrote: > Hi, > > I think since address B is different from address A, client should > treat this as some NAT is in place should send responses back to address A > which is actual source IP received in Packet. Here, client can also treat > that Layer 3 ip and layer 2 ip are different and thus same logic of NAT > should be applied and response should be sent to source IP. > > Refer NAT detection procedures for more details. > > Thanks and Regards, > Vivek > > > > On Fri, Sep 19, 2014 at 6:23 PM, Kchitiz Saxena <kchitiz.sax...@gmail.com> > wrote: > >> Hi >> This is related to UAS behaviour to know "Where to send response for the >> received request". Following two statement looks a bit contradicting to >> me - >> >> 1. RFC 3261, Section 18.2.2 - The server transport uses the value of the >> top Via header field in >> order to determine where to send a response. >> Same section, last bullet - >> Otherwise, if it is not receiver-tagged, the response MUST be >> sent to the address indicated by the "sent-by" value, using the >> procedures in Section 5 of [4]. >> >> 2. RFC 3263 - A server, according to RFC 3261 [1], will send a response on >> the >> connection it arrived on (in the case of reliable transport >> protocols), and for unreliable transport protocols, to the source >> address of the request, and the port in the Via header field. >> >> As per RFC 3263, it seems like only port is used from Via header and >> source >> address is used. Although, I believe that Address and port both should be >> used from Via header and RFC 3261 also indicates the same. Does this >> statement from RFC 3263 applies to some special situations? >> >> >> My problem is following- >> Application receives an INVITE message from source IP address A with FQDN >> in Via header. FQDN is resolved through DNS A query and receives DNS reply >> where IP address B is mentioned at top and IP address A is mentioned after >> that. So, all the responses are sent to IP address B. Calling side keeps >> retransmitting the request from source address A and call does not go >> through. Is there anything which can be changed in application's >> behaviour? >> >> Thanks >> Kchitiz >> _______________________________________________ >> Sip-implementors mailing list >> Sip-implementors@lists.cs.columbia.edu >> https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors >> > > > > -- > > Name | Title > GlobalLogic > P +x.xxx.xxx.xxxx M +x.xxx.xxx.xxxx S skype > www.globallogic.com > <http://www.globallogic.com/> > http://www.globallogic.com/email_disclaimer.txt > _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
