> > Both at home and at work there are caching DNS on the LAN. So a DNS > request may come back with a valid IP address when the WAN connection is > down. I still won't be able to connect to the remote site.
Dig an external server - e.g. dig @a.root-servers.net google.co.uk If your net is down the query will fail even if the reply is cached locally, because you're specifically requesting a response from a.root-servers.net.