An upstream service provider of ours has identified an issue with one of their high volume routers and are currently performing emergency maintenance on it. This has caused an outage on the following servers:
web331 web332 web333 web334 dweb148 dweb155 dweb156 dweb159
We will update this post as soon as the issue has been resolved.
2012-10-17 5:36 UTC: The problem has now been resolved and all servers are back online.