This was sent to me by the ISP, hopefully the outages will be brief...

Some of you may have noticed intermittent problems with Internet connectivity in general over the past few days. Cisco has recently released major security patches in order to to patch core router vulnerabilities in their networking equipment. Networks across the globe have been busy updating their Cisco routing equipment, meaning that many networks have been sporadically unreachable. We expect this to continue across the Internet over the next week.
The datacenter that houses the server your site is on will begin performing security upgrades between the hours of 1 AM and 6 AM Saturday, July 19th. Please be aware that this upgrade is occurring, should any unforeseen unreachability be experienced.