rsync protocol description

Christoph Bartelmus rsync-list at
Wed Dec 18 08:08:01 EST 2002

Donovan Baarda wrote:
> > For that I'd be very much interested in a description of the protocol
> > that rsync talks on port 873. Is such a description available somewhere?
> > I don't want to have to deduce the protocol from the source code.
> The protocol changes as rsync is updated, and is very.... evolved....

Does that mean that rsync does not maintain downwards compatibility? My
former examination did not indicate this. The startup protocol includes
the exchange of protocol versions in use. I guess there's a reason for
it. Otherwise I could imagine that this could be a steady cause of

> re-implementing and tracking it is not really viable/desirable.
> > What I have found so far are the description of the algorithms (rsync
> > technical report and Andrew Tridgell's PhD thesis). Have I overlooked
> > something obvious?

The ftp-server gives me a "421 Service not
available, remote server has closed connection".



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