MJ Ray wrote:
It's possible, but I didn't have particularly good results with this as a failure cover. What seems to happen is that when the distant server fails, the caching proxy can't detect that for a while (because DNS is usually over UDP which is usually stateless, IIRC) and you end up with many caching proxy requests hanging.
I'd be interested to know more about this, as presumably DNS over TCP instead of UDP would solve this, but I suspect that the problem might turn out to go deeper (the sort of thing you find out when it's least easy to do something about it...)
If the caching proxy has a way that you can flip a switch so it will serve everything from cache when the primary DNS goes unavailable, then it might work, but I've not found one that offers that.
The DNS proxies I looked at seemed very inflexible, to be honest; presumably they weren't aimed at this "market". That's why I dened up asking here about ways to go.
Moving things away from 123-reg is a very good idea! I've had trouble with them and I think they were in Martyn Drake's Feckwits category for quite a while (or was that fasthosts? Both pretty bad IMO.)
I've generally had good results from 123-Reg for domain registration and DNS, so this one has surprised me. What I have liked about them in the past is that generally I can do everything I need to easily and cheaply (including just letting them register the domain then use them to change the DNS settings to something under my control). I don't have the knowledge or resources to set up and manage multiple DNS away from 123-Reg, although managing one which I only really need to worry about in rare circumstances isn't so bad (if I have to take it down for a couple of days to move it to another server its no big deal unless it coincides with another outage).
Most 3rd party DNS providers I've looked at charge on a per-domain basis which would make migrating all the domains we currently manage a big expense for little paypack; a lot of our customers like to have a few dozen domains all pointing to the same place and with pretty much just "www" in the DNS (often not even MX records).
Maybe I'll look at a couple of cheap hosting companies in different locations and use them just for this on the basis that losing them all together is pretty unlikely!