After seeing two back-to-back DNS infrastructure outages in a single week, I've got a message for Comcast. DNS is not rocket science! My fellow blogger Phil Windley had this to say about the recent catastrophe that affected millions of Comcast customers. I've got some advice that might get him and his fellow Comcast users some relief the next time they suffer a DNS outage. Contrary to the popular belief of some IT departments and IT analysts, DNS infrastructure isn't expensive and is extremely easy to cluster (a way to scale performance and survivability). DNS caching servers (the type of DNS that went down for Comcast customers) is so ubiquitous that it is pretty much built-in to most flavors of UNIX including Linux and Mac OS, Windows server operating systems, and even most consumer-class routers (discounted as low as $30) from vendors like Linksys, Netgear, D-Link, Microsoft, and Belkin.
For an operation like Comcast, there is absolutely no excuse that they couldn't simply build two or more distributed clusters of DNS caching servers using pizza box-sized generic servers that cost less than $1000. Although the use of generic commodity servers is heavily sneered upon in "elite" IT circles (usually the same people that think DNS is hard to implement), it's actually part of the secret sauce that makes Google tick. In this case, DNS caching is much simpler than anything Google has to do and therefore is an even better candidate for cheap commodity clusters.
But while Comcast tries to figure this out, are their customers suppose to sit around for a possible third DNS outage? The answer is no, and they can do something about it if they're not looking for a new ISP. Phil had linked to a nifty site that posted simple instructions for setting a Mac as a DNS caching server. The Linux people probably already know how to set up their own DNS. Unfortunately, that leaves in the dark the other 90% of the computing population who happen to be on a Windows desktop operating system. Fortunately, you have an even simpler solution that can fix all the computers in your home. All you need to do is turn on the DNS capability in your Internet sharing router. Sometimes you may have to perform a firmware upgrade that you can download for free from your equipment maker's web site. For Linksys users, there are tons of third-party firmwares you can find here.