This morning the internet all of a sudden stopped working - no big deal, the router's only been up for something like 300 hours, probably just needs a reboot. Prior to rebooting I noticed that we still had connectivity - weird. After some investigation, I worked out that we're receiving two DNS servers via DHCP:
... and they weren't functioning. Interestingly enough, after setting my DNS servers to
ns1.exetel.com.au resolved to
188.8.131.52, and was resolving correctly. So it looked like it was in fact an outage on Exetel's part. Off to their help desk to file a ticket.
Update: an hour or so later, they explained that it was indeed a nationwide outage with their DNS server and it should be back up and running.