[rc5] Behind a firewall

Mike Montour mmontour at unixg.ubc.ca
Thu Aug 28 19:37:25 EDT 1997

Greg Wooledge wrote:

> Since you're getting the banner (at least sometimes), you're talking
> to
> the proxy.  Anyone unfortunate enough to have to use the HTTP proxy
> method
> is going to have to deal with intermittent communications failures --
> it
> just isn't robust enough. :-(  But let it run!  You'll occasionally
> connect
> to deliver and fetch blocks, and at other times you'll process random
> blocks -- it's a whole lot better than nothing at all.
> I tried replacing the preferred proxy address with a randomly chosen
> IP
> address out of the set that rc5proxy.distributed.net maps to.  It does
> seem to help at least a little bit (not completely better, but it's
> certainly no worse).  I'd still like to know why.

I've had the same problem, and haven't verified the cause (didn't need
to, after
I got a personal proxy running on the firewall box). My hypothesis was
that because
"rc5proxy.distributed.net" returns multiple IP addresses, maybe the
HTTP server
was initiating a connection with one of them, but switching to another
one in the
middle of the key-fetch process (which presumably includes a bit of
handshaking). This could make sense with HTTP, which is a stateless
protocol (every
request is independent of any previous communication between your
computer and
the server). However, for keyblock transfers, this could result in
"rc5.darkstar.net" sending you a keyblock, but "rc5.slacker.com"
receiving the acknowledgement. If you hardwire an IP address as your
preferred proxy, you avoid this problem.

As I said, this is only a hypothesis. Any comments?

BTW, I found that "rc5.darkstar.net" worked well from my location, but
your routing
may vary.

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