[tahoe-dev] Troubleshooting node connectivity

[Shawn Willden]

While checking my backups I've noticed a problem: two of the nodes in my 
friendnet aren't reachable by others.  I'm pretty sure it's not a 
NAT/firewall issue, because those nodes ARE reachable by two other nodes.

Currently there are seven nodes in my friendnet, three of which are rarely 
running because they're on Windows boxes, and I haven't got around to 
figuring out how to reliably run Tahoe as a service and haven't convinced the 
users that they always need to start it up whenever they log on.

Of the four reliable nodes (two running on Lenny, two running on Ubuntu 9.10), 
the two Lenny boxes can connect to the two Ubuntu boxes, but the Ubuntu boxes 
can't connect to one another.  I think the association between OS and 
connectivity is coincidental.  My guess is that the real issue is that the 
two Ubuntu boxes are behind NATing routers.

The routers for both have them have been configured to forward the web 
interface port and the client port to the machines.  I've verified 
connectivity to both of those ports in both cases, and the Lenny machines can 
connect to both nodes.

One of the two Lenny machines is an LVS in a co-lo with no firewall.  The 
other is connected directly to a cable modem.  It's running a fairly tight 
iptables firewall, with appropriate holes poked in it.

Any idea what the problem might be?  What can I do to get more visibility into 
what connections Tahoe is attempting to make (and failing)?

Thanks,

	Shawn.