Path: utzoo!attcan!utgpu!watserv1!maytag!xenitec!zswamp!root
From: root@zswamp.fidonet.org (Geoffrey Welsh)
Newsgroups: comp.dcom.modems
Subject: PPP spoofing, NetBlazer (was Re: Telebits "PEP" protocol)
Message-ID: <6547.277047AD@zswamp.fidonet.org>
Date: 19 Dec 90 18:07:24 GMT
Organization: Izot's Swamp BBS - Kitchener, Ontario
Lines: 36

Bob Sutterfield (bob@MorningStar.Com ) wrote:
 >UUCP spoofing works because uucico's ACKing and retransmission
 >is at the granularity level of a complete file.

   Where did you get this little gem? UUCP-g ACKs (or request retransmission) 
of each and every packet on a real-time basis.  Surely you don't believe that a 
burst of line noise could cause the retransmission of a complete newsbatch?!?

 >The "g" protocol level doesn't manage file retransmission or restarts
 >in mid-file.  Kermit spoofing is similar.

   This has no bearing whatsoever on spoofing.

 >But TCP streams think that, once a packet has been ACKed, it has been
 >delivered to the receiving end.  Retransmission and restarts happen 
 >at a packet granularity.

   This is also true of UUCP-g.

 >If part of the circuit between transmitter and
 >receiver were to accept responsibility for delivery of a packet after
 >ACKing it to the transmitter, it would destroy the end-to-end nature
 >of TCP.

   Not if it could guarantee accurate delivery of the data to a device which 
would retransmit it to the final destination if it were to be NAKed... that is 
the way spoofing works.
 

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