We've had some odd DNS problems over the past couple of days that I don't fully understand.

Some of our DNS names stopped resolving for some of our customers due to some 'unknown' server reconfiguration at our DNS provider.

The problem seemed to be intermittent i.e. stopped working and started working within a few minutes over a couple of days.

I'm no expert on DNS, but I'd have expected DNS caches to prevent this sort of thing from happening - when we need to change an IP address for a DNS record, it can take 24 hours to propogate, so how can our DNS provider be breaking name resolution intermittently for our customers so easily? Shouldn't the DNS caches kick in here?

We had a similar problem about a month ago when one of their nameservers 'decided to reload the DNS database from scratch' - this broke our name resolution too. Again, why didn't the caches satisfy the name resolution requests.

Any guesses would be appreciated. John