Semiregular Interruptions to Broadband

[#1]

My broadband service hangs up from time to time. It's done it for years on ADSL and still doing it on Fibre but it seems to be getting worse. I'm sure hardly a session passes without losing connectivity at least once.
It only does it for a few minutes and comes back with no action needed from me. Doesn't matter what I'm doing or what PC/Laptop/Tablet I'm using at the time. When it drops out the router (TG582n) still reports that all's well and the connection is OK but any pings outside the LAN fail to find the target. It acted similarly on ADSL with my Netgear router.
I'm sure it's nothing at my end - any ideas how I can address this irritation?

[#2]

Hi,
I've posted a log of your connection;
<img src="http://ccgi.psmith12.plus.com/visradius/generated/image13567153746094.png"/>
This shows as you said that your connection is still working. Are you connecting wireless or wired with your devices? If it's both are the wired one's working when the wireless aren't?
Chris

[#3]

When pings fail do both
ping ntp.plus.net
and
ping 212.159.6.9
fail?

[#4]

I've not tried pinging an IP (never can remember one when it's needed), I've only tried by name. I'll take a note for the future.
When connectivity is lost the first sign on a browser is 'waiting...' then a refresh changes it to 'looking up... so I suspect that in the first case the target IP is actually known but I'll check this out.
Thanks.
Thanks for the confirmation Chris - as I said, and you've confirmed, the actual link is still there but no connectivity. The odd dropout that you show was a separate thing when I needed to move some things around.
When it drops out everything loses WAN connection together but internally things are still OK. I do have a couple of servers running full-time so I wonder if one of them is doing something strange?

[#5]

Quote from: jelv

When pings fail do both ....(name and IP addy)

And of course that was it!
After a bit of head scratching I realised that a few of my machines had been left set up getting their dns from a little server which for some reason best known to itself was sometimes too busy to bother serving it out.
Sorted.