On Sat, 2006-10-07 at 10:52 +0100, Mark Rogers wrote:
I have two ADSL lines from completely different providers (Demon and The Phone Coop (www.thephone.coop), both behaving the same. The lines are both in the Peterborough area but on different exchanges. Although this isn't a Linux problem I think Linux is most likely to give me the tools to resolve it.
Basically, some of the time the ADSL lines just work: I can browse the web, collect email, download ISOs, etc.
However the rest of the time (and its becoming increasingly "most of the time") I can't. To all intents and purposes the connection has gone.
Very strange.
Some of the things you mention below almost sound like a MTU miss-match problem, but why this would be intermittent I am not sure. MTU problems could explain why a ping works until the packet size is increased and could also explain why traffic encapsulated by your VPN may work while other connections fail.
What are the line stats on your routers showing ? It doesn't sound completely like an ADSL/Line problem but the intermittent nature sort of points in that direction.
When you are in a state of not being able to start a new ssh connection can you still telnet to port 22 of an external ssh server and see the server banner (or do you get connection timed out even doing that)