ADSL problem... any ideas?

[Dave S]

On Saturday 06 October 2007, Dave S wrote:
> They tested the connection from their end, and apparently it was working
> fine. It was also working fine on the old router - the problem is this
> "new" (reclaimed from another office) router, I'm sure of it.

OK fixed it!

It wasn't the D-Link router - this was proven when I got the old router 
working again (new PSU needed, that's all) and the problem was exactly the 
same.  The D-Link isn't being used now, since the old router was better 
anyway.

After much probing and tracerouting, I spotted that the domains it was bombing 
out on all seemed to die at the same point in the route (slightly annoyed I 
didn't spot this earlier, but I thought our new router was the problem, since 
apparently it was working with the old one).  This same point was working OK 
for the domains that worked, but for the broken domains, they all died at the 
fourth hop - just upstream of the ISP.

Got the ISP to assign us a new fixed IP address and everything was fine, 
though I hope they'll look into it some more, as that's a seriously weird 
thing.

They reckoned the IP address might have been in use for something before, so I 
guess it probably was the reverse resolution, since the packets were probably 
being sent off somewhere completely different by a borked DNS entry 
somewhere.

It was a routing error at the ISP after all that... sigh!

Thanks for the help everyone, much appreciated!

~Dave