One of the car forums I'm a member of went down the other day. Firefox reported site not found.
It has a 'sister' forum as a Facebook group, and it seemed only those using BT Infinity had lost the main forum. And the forum administrator reported that changing the DNS server in his BT router got it working on his PC.
However, it seemed to be sorted a couple of days later without doing anything here.
What are the pros and cons on changing the DNS server that BT expects you to use?