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Re: Proxies and loops

From: Jeffrey Mogul <mogul@pa.dec.com>
Date: Mon, 18 Dec 95 13:58:19 PST
Message-Id: <9512182158.AA19343@acetes.pa.dec.com>
To: Duane Wessels <wessels@colorado.edu>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
    I totally agree that a HTTP-traceroute will be very useful.  However, I
    don't think we need TTL to do it.  If I understand correctly,
    traceroute uses increasing TTLs because the IP LSRR option is/was not
    always implemented, and the fixed IP header size limit only allowed
    something like nine addresses to be recorded.  Since HTTP doesn't
    suffer from either of those problems, wouldn't it be better to just
    have the Forwarded lines included in the response header?  Then you
    only need to make one request.
Since you jumped into the middle of this thread, you may not have
seen the second message I sent on this topic.  Roy Fielding raised
much the same point, to which I replied:

    TRACE suffers from the same problem as the IP "record route" option:
    it's useless if the path is broken.  (Loops are not the only way
    to break a forwarding path; it's probably even easier to do that
    by misconfiguring a "proxy" pointer to point at a black hole.)

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Received on Monday, 18 December 1995 14:09:18 UTC

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