Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!haven!mimsy!nile.cs.umd.edu!dheeraj
From: dheeraj@nile.cs.umd.edu (Dheeraj Sanghi)
Newsgroups: comp.protocols.tcp-ip
Subject: IP_LSRR Option - how is it implemented?
Message-ID: <19206@mimsy.UUCP>
Date: 22 Aug 89 03:09:02 GMT
Sender: nobody@mimsy.UUCP
Reply-To: dheeraj@nile.cs.umd.edu (Dheeraj Sanghi)
Organization: Comp. Sci. Dept., Univ. of Maryland, College Park, MD 20742
Lines: 28


Hi,
	I want to know what happens when I set the IP_LSRR option.
Let us assume a client-server model. The client just sends some fixed
number of packets to the server. The client wants to route the data
via gateway X, and the server wants to route the acks via gateway Y.
Client calls setsockopt and gives the next hop as X and 2nd hop as
the machine running the server, and everything goes fine. Now, server
doesn't know which machine is going to connect to it, so it can't
set the LSRR option, it would seem. What I am doing is setting the
next hop to be Y, and setting the final hop to be a random number.
Surprisingly, I do get the acks and the data goes through fine.

	Now I tried to look into the TCP/IP code (4.3 BSD) to see
if somewhere it "fixes" the final hop, but I don't seem to find any
such code. Would anyone explain me what's happening? To me it seems,
that the server should just send the ack packet to Y, which can't send
the packet any further (after all it sees an address, it doesn't know
about, I am using 0.0.0.1 as the "random number")

thanks in advance,

-dheeraj

Dheeraj Sanghi			(h):301-345-6024	(o):301-454-1516
Internet: dheeraj@cs.umd.edu	UUCP: uunet!mimsy!tove!dheeraj
	Namaste sada vatsale matrabhume,
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