From ICTS this evening:

Dear UCT staff and students,
In order to try to resolve the DNS problems affecting Internet access and external mail delivery, we need to reboot our edge router at 17h00.
IMPACT:
The restart should take about 10 minutes.  During this time, there will be no access to the Internet and no internet mail will be delivered.  All mail will be queued and delivered once the router is back up.
Thank you for your patience while we restore services.
Regards,
ICTS Communications
Plus ca change, plus c'est la same chose....