My connection to the Internet is via an ADSL line through BT (UK), but at random times my router just disconnects and won't reconnect without a full reboot. I have used three routers since I had the line installed; Belkin, Netgear and now Draytek Vigor, and they all display the same symptoms. All have had an option to "auto-reconnect" or "keep connected" or similar, but it doesn't seem to work. The router's firmware is fully up to date.

Does anyone know why this could be?

In my experience (I look after 4 BT-connected linux networks) BT has been very relaible. I have used a variety of ADSL modems / routers, including netgear and Zoom. They have all worked extremely well.

Your internet connection is managed by your modem/router/switch (which is probably running linux, most do), but the fault lies not with your distro but either with your ISP (bad exchange equipment, maybe long, noisy landline) or, more likely in your hardware at home: Many "DSL Filters" - the things you have to plug all your phones into, are of very poor quality, and need replacing until you get good ones. So I'd recommend you unplug phones and filters and swap things around a little. There may well be a fault on one of your filters.

There are two ways of setting up the incoming DSL connection:

1] You put a filter on the master socket: the DSL signal is sent to your modem, and the filtered signal is sent to your phone(s). In this case your phone(s) do not need individual filters. This is probably the most relaiable way to set things up.

2] You plug a DSL splitter into (any) socket, and connect your phone and DSL modem. If you do this, then every other piece of equipment plugged in to your phone line must have a DSL filter attached. And that filter must be working. Many of them are bad, cheap imports from you-know-where

If you have 15 "phones" in your house (count them up - phones, cordless phones, television, burglar alarm modems and whatnot, then simplify it, or, better, go for option[1] above - it filters out the DSL signal early on.

Experiment, then get back to us.
HTH

Ahh, I never thought to consider the filter quality. I am using the standard ones from BT that were supplied when I first got ADSL (when we moved in). Currently nothing is plugged into the master socket, but two lines split off. Ones goes upstairs to a socket which has a filter feeding the ADSL modem/router, and a cordless phone. The other goes to another socket which also has a filter, the voice side of which is split and fed to another cordless phone and a SkyDigital box. Can you recommend any good quality filters I should try?

In case this helps, according to the router its current signal to noise ratio is 17.0 (which I assume is db), and loop attenuation is 36.5. Unfortunately I have no frame of reference to know if these figures are good or bad.

No. Sorry.

Every bit of DSL kit I have bought / been given "free" has come with at least two filters, so I now have a few spares. One of the networks I "manage" (I'm the family "guru") was badly broken. It eventually turned out, by a tedious process of elimination, to be a bad filter (BT supplied, as it happens).

Beg, borrow or buy some different filters & swap things around. If no improvement then you should contact BT, there may be a fault at their end.

shitty line i expect.... have you checked what the line loss details are and such? if you use voyager routers check the dsl line status in there and you can get a lot of useful details, for example if the line loss margin is under or approaching 12dB then you may benefit from reducing the line to a lower speed which would improve that a lot. also you've other usual suspects like disconnecting all other equipment from the pstn line including exntsions in other rooms etc...

Well, it's funny, but since posting this it hasn't disconnected since! I still have some experiments to do though. I have 3 filters plugged in at various points and which I intend to isolate and test individually. Currently, according to my router setup screen, my signal-to-noise ratio is 24.0 and loop attenuation is 37.0. I am assuming these figures are dB, but have no frame of reference to decide if they are good or bad. Once I have experimented I'll post more info.