From: "Harry Hochheiser" <harry@tigger.jvnc.net>
Date: Sun, 14 Jul 1996 04:09:07 +0800
To: cypherpunks@toad.com
Subject: Re: ANNOUNCEMENT: PGPfone Beta 7 Now Available for Download
Message-ID: <199607131509.AA14392@tigger.jvnc.net>
MIME-Version: 1.0
Content-Type: text/plain


On 12 Jul 96 at 21:31, Arun Mehta wrote:

> At 23:38 10/07/96 -0700, Will Price wrote:
> >ANNOUNCEMENT: PGPfone Beta 7 Now Available for Download
> 
> Sorry if this has been discussed before (please point me in the
> right direction if that is the case), but VSNL, my government-owned
> ISP (which also has a monopoly on all international traffic) made me
> sign that I will not use my Internet connection for voice traffic.
> Is there any way they could find out if I were using PGPfone, or
> rather, could I prevent them from finding out? 


Arun:

I can't give you a definitive answer here, but I'll take a shot.  
Most Internet telephony systems use UDP packets to transfer speech, 
since the lower overhead of UDP (as opposed to TCP) allows for better 
throughput.      I assume (but I'm not certain) that PGPfone works 
the same way.

Unfortunately, most of your other TCP/IP communication will be based 
on TCP packets.  Therefore, it's theoretically possible for your ISP 
to monitor your traffic, watching for large numbers of UDP packets.  
While a large amount of UDP traffic wouldn't _prove_ that you were 
using Internet telephony, they might _assume_ that the UDP traffic 
was voice traffic.  It all depends on how sophisticated and 
heavy-handed they wanted to be about it.

Now, I don't know if PGPfone uses UDP.  However, if it did, it would 
be as easy to detect as any other Internet telephony product.  An 
encrypted bunch of UDP bits is as easy to spot as an un-encrypted 
bunch, even if the contents can't be interpreted.

I hope this helps.  If any of this content is incorrect, my 
apologies.

-Harry



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Harry Hochheiser           harry@tigger.jvnc.net
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