[OpenSIPS-Users] NATed REGISTERs are failing

[Andrew Pogrebennyk]

Hello Jeff,

Jeff Pyle wrote:
> Iñaki (or anyone),
> 
> Can you tell me where in RFC3261 it refers to, "...if a proxy receives a request in which Via sent-by differs from real source address, then 'received=PUBLIC_IP' must be added to top Via."
> 
> I'm in the process of fighting another battle where this information would be very, very handy.  I can't seem to find it myself.
> 
> Thanks,
> Jeff

RFC 3261 point 18.2.1 states it clearly:

    When the server transport receives a request over any transport, it
    MUST examine the value of the "sent-by" parameter in the top Via
    header field value.  If the host portion of the "sent-by" parameter
    contains a domain name, or if it contains an IP address that differs
    from the packet source address, the server MUST add a "received"
    parameter to that Via header field value.  This parameter MUST
    contain the source address from which the packet was received.  This
    is to assist the server transport layer in sending the response,
    since it must be sent to the source IP address from which the request
    came.

Actually, RFC 3581 (rport) updates this behavior:

  4.  Server Behavior
    ...
    In fact, the server MUST insert a "received" parameter
    containing the source IP address that the request came from, even if
    it is identical to the value of the "sent-by" component.

-- 
Sincerely,
Andrew Pogrebennyk