Privoxy usage?

nobledark at hushmail.com nobledark at hushmail.com
Sat Aug 18 16:20:12 UTC 2007


I have heard of the "TCP over TCP" issue but have not had any bad 
experiences so far. I am currently using both TCP and UDP-based VPN 
systems and while the TCP-based one is a bit slower, it still seems 
very stable for applications such as Terminal Services, FTP, 
http(s), etc. 

I do notice problems with some apps (FTP for example) if I'm trying 
to use a TCP-based connection over a satellite link - lot of TCP 
RSTs and "Zero Window"-type errors in the sniff though on some 
satellite systems even UDP-based tunnels don't seem to work very 
well for anything other than low bandwidth applications.


Thanks again...Nd

On Sat, 18 Aug 2007 11:52:46 -0400 Michael_google gmail_Gersten 
<keybounce at gmail.com> wrote:
>On 8/18/07, nobledark at hushmail.com <nobledark at hushmail.com> wrote:
>> I have several options - what's the issue w/ using TCP?
>
>TCP over TCP has some problems, the least/biggest of which is the
>timeout factor.
>
>If there is a communication problem, TCP has a "back off and 
>resend"
>rule. This starts with "I didn't get an acknowledgment. I might be
>sending data too fast, or data might have gotten lost. I'll pause 
>for
>two seconds, and then send the data again".
>
>The problem? If the low level TCP stream does this, then any 
>higher
>level stream with data in transit will also see a delay, and a 
>need to
>re-transmit.
>
>I may be doing a horrible job of explaining the problem. A simple
>terminal session may have no problem -- a single packet of data 
>will
>eventually get an acknowledgment back.
>
>But if there is a stream with more and more data behind it, then 
>you
>wind up with an ever increasing resending that never gets caught 
>up.
>Eventually all the TCP channels break.
>
>TCP was designed with certain assumptions in mind. It does not 
>work as
>a general purpose transport -- that was never it's goal.
>
>IP over IP works.
>UDP over UDP works if your UDP protocol supports it.
>TCP over TCP fails. The timeout rules cannot stack properly.

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