[52019] in Cypherpunks
Re: FCC & Internet phones
daemon@ATHENA.MIT.EDU (Adam Shostack)
Tue Mar 12 10:08:34 1996
From: Adam Shostack <adam@homeport.org>
To: gary@kampai.euronet.nl (Gary Howland)
Date: Tue, 12 Mar 1996 09:32:58 -0500 (EST)
Cc: cypherpunks@toad.com
In-Reply-To: <199603121049.FAA20806@bb.hks.net> from "Gary Howland" at Mar 12, 96 05:49:40 am
Gary Howland wrote:
| Adam Shostack wrote:
| > Loren James Rittle wrote:
| > | >Most
| > | >presumably use a mix of a UDP data connection and tcp for control
| > | >functions.
| > |
| > | OK, everything after the IP header is encrypted. I don't even know
| > | which protocol is in use.
| >
| > Are you willing to play Mallet? Drop IP packets, and look for
| > duplicates. Those are TCP. (IPSEC might handle this, but I bet there
| > will be broken implementations that save time by resending.)
|
| Are you saying UDP protocols don't retransmit un-acked packets?
| If not, then you can't be sure the duplicates are TCP.
Err, yes. Thats the point of UDP; its unreliable and has no
acknowweldgement.
"The User Datagram Protocol uses the underlying Internet Protocol to
transport a message from one machine to another, and provides the same
unreliable, connectionless datagram delivery semantics as IP."
(Comer, 11.3)
Adam
--
"It is seldom that liberty of any kind is lost all at once."
-Hume
