AW: AW: Re: Patch for Socks5 support for dynamic portforwaring?

[Alex Peuchert]

Well, SOCKS5 supports UDP forwarding ... so if openssh dynamic port
forwarding ( -D ) would support the SOCKS5 protocol then openssh would
include UDP forwarding from/to a remote host!

Wouldn't this be really cool?

- alex

> -----Ursprüngliche Nachricht-----
> Von: Dan Kaminsky [mailto:dan at doxpara.com]
> Gesendet: Mittwoch, 25. Juni 2003 11:46
> An: Alex Peuchert
> Cc: Markus Friedl; openssh-unix-dev at mindrot.org
> Betreff: Re: AW: Re: Patch for Socks5 support for dynamic portforwaring?
>
>
>
> >good point ... so, what would be the solution if I need some kind of UDP
> >port forwarding?
> >
> >
>
> This is actually problematic over SSH.  SSH presumes a lower layer will
> provide basic reliability -- it runs over TCP.  Port forwarding is a
> method of doing TCP-in-TCP encapsulation; usually this has serious
> performance issues as both sockets implement backoff et al, but SSH
> avoids these problems by locally terminating the socket,
> de-encapsulating the payload, and sending only that payload over the
> tunnelled link.
>
> This works because TCP is byte oriented and the only thing that matters
> is the order of the data.  Such is not the case with UDP -- it's just a
> very thin wrapper on top of IP and anything goes regarding how the
> payload is transferred.  The literal length of each packet is relevant
> is a way that doesn't exist for TCP.
>
> That being said, a piece of Paketto (my own bizarre packet-mangling
> code) may help with this...I'll see what I can get into the July
> 30 release.
>
> --Dan
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