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From: hahn@tolerant.com (John Hahn)
Newsgroups: comp.protocols.tcp-ip
Subject: IP-X25: Whatif no calling x25 addr?
Keywords: IP, X25, DDN
Message-ID: <1990Mar3.042557.15312@tolerant.com>
Date: 3 Mar 90 04:25:57 GMT
Distribution: usa
Organization: Tolerant Software
Lines: 20

I am in the midst of implementing an IP-X25 solution for my company's Unix
based OS. One issue which I am trying to resolve is the actions that
the IP-X25 software must take on situations which involve incoming X25call
requests to IP.

First of all we are dealing with non-ddn PDN world so that ip-x25 addresses are
mapped from some configuration table. So all incoming call requests require
a calling address which need to be mapped to an ip_address so that this
particular VC will be bound to an ip_address. BUT what can you do if there
is no calling address present?? This is not a required field in X25 spec 
and many do not bother using it. Obviously one can simply require it. One
is tempted to look at the ip datagrams which will be coming through the VC
and extract the src ip_addr and attempt to use it. This src ip addr ,however,
may NOT be the ip addr of the remote IP-X25 host. But even this seem a lot
what better than just refusing the connection.

If any one can share some of their experience in this matter it would be
greatly appreciated. Thanks in advance.

john.