Re: SIP Dialog Match

Well, strictly speaking, this is possible and most SIP networks are
vulnerable to this. This is no different from HTTP or SMTP where this is
possible.

The guidelines (there could be others as well) to overcome this are:

1. Implement a known-good-source kind of logic where you accept
responses coming only from a well known proxy. Ofcourse, this works only
when there is a proxy and when the source IP address of the response
itself is not modified.

2. Implement encryption (e.g. TLS) for signaling

Regards
Satya T

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Karunesh Sharma
Sent: Friday, August 07, 2009 6:37 PM
To: Dale Worley
Cc: [email protected]
Subject: Re: [Sip] SIP Dialog Match

Dale:

It's simple scenario where 'A' sent INVITE to 'B'. 'C' is man in middle
captured the INVITE and sent the response back to 'A'. I wonder why no
one ever had such case ever and why there is no established guidelines.

K$
_______________________

-----Original Message-----
From: Dale Worley [mailto:[email protected]]
Sent: Monday, August 03, 2009 9:35 PM
To: Karunesh Sharma
Cc: aayush bhatnagar; [email protected]
Subject: RE: [Sip] SIP Dialog Match

On Mon, 2009-08-03 at 21:28 +0530, Karunesh Sharma wrote:
> Is this a valid behavior for scenario like 'Call-Forwarding'?

In principle, the responses to a request should almost always come from
the address to which the request was sent.  But that is not usually
enforced, and there may be good reasons why it isn't happening in a
particular instance.

In regard to an observed instance of this behavior, you must first
determine the complete routing of the request in question and the reason
for each routing step.

Dale


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Sip mailing list  https://www.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [email protected] for questions on current sip
Use [email protected] for new developments on the application of sip