[bittorrent] Re: Re:

Justin Cormack justin at street-vision.com
Sat Apr 23 09:23:33 EDT 2005


(cc to list)

On Fri, 2005-04-22 at 21:56 +0000, larytet.8708132 at bloglines.com wrote:
> "You could make a client that passes well formed DNS queries to the real DNS
> server though..."
> 
> that's interesting idea, i will add it to the existing
> design.
> 
> anyway i am pretty sure that the moment Rodi gains popularity firewalls
> will implement DNS relay and will parse DNS packets. i give it 6-12 months
> top before commercial firewalls come with solution. 
> 
> Faked HTTP/HTTPS is
> a reliable way i see to work around the intelligent firewalls. holes like
> destination port 53 (and some others) are going to be closed fairly quick.
> even simple traffic policy like up to 100 DNS reuqests/s will prevent using
> DNS for data transfer over high speed connections.

there are audio and video streaming servers over well-formed DNS, but
its a hack....

> to fake HTTP sessions
> i will have to use raw sockets (i need to fake TCP handshake as well to fool
> the firewall/NATP). not an easy task and code is not going to be portable.

At that point you may as well just use a tcp session, as faking one will
have the same overhead.
> 
> One of the functional requirements in Rodi that you can receive (collect)
> packets and answer/reply to the requests using different IPs and even different
> PCs. For example, request can be routed through the ring of bouncers - supported
> by the existing code, but reply is sent direclty to the peer.
> 
> Another alternative
> is RTP. Shaping of RTP is not easy for ISPs from marketing point of view.
> 
> 
> Not to say that i am not ready to help ISPs. Part of the desing is URL
> based data requests. If ISP decides to cooperate Rodi can leverage existing
> HTTP caches (not supported by the code today)

Its a lot of work just to deal with very confined environments, not sure
I would spend that much more effort on it.





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