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DNS: Once again, Comcast fails the test

-July 25, 2013

Since I'm now accessing HBO GO via my Xbox 360 using a LIVE Gold membership, I went ahead and recently set up my console to auto-log into my LIVE account. For the first few days, all was well. Then, I started getting LIVE login errors, which the Xbox 360's built-in diagnostics indicated were caused by the fact that the "DNS server can’t resolve Xbox LIVE server names." This was odd, because in all other respects my Comcast broadband connection seemed to be working fine. The suggested resolution was for me to turn the console off, turn my cable modem and router off, wait a few minutes, then power back up the cable modem and router and, after waiting for them to boot and re-establish a connection with Comcast, turn the Xbox 360 back on.

This "fix" was tedious and otherwise annoying but did the trick, at least for the first several iterations. The console would subsequently log into Xbox LIVE on boot, as it had done before, and continue to do so for a few days ... until it failed again, at which point I'd repeat the procedure. But the "fix" eventually stopped working, too; no matter how many times I power-cycled the modem and router, I wasn't able to log the console into Xbox LIVE. On a hunch, based on the "DNS server can't resolve" aspect of the error, I hard-coded Google's Public DNS lookup IP addresses into my router. In doing so, I was overriding the DHCP-assigned Comcast DNS server addresses that my modem had received and passed along to the router, which it then passed along to my DHCP-assigned LAN clients.

Surprise surprise ... the Xbox 360 went online immediately, and has continued to consistently do so ever since ... with the exception of the one time when, to confirm both the fix and the root cause of the problem, I removed the Google Public DNS settings and once again was unable to log into my Xbox LIVE account. In retrospect I realize that previously, in power-cycling the modem and router, I was forcing a DHCP renewal of my broadband connection (including the DNS server assignments), although periodically jumping through this hoop shouldn't have been necessary at all, and don't know why it no longer does the trick. And in retrospect, given my to-date track record with Comcast, I probably shouldn't have been surprised at this latest morass.

Plenty of others have, I've subsequently realized, experienced the same issue. And the situation frustrates me both personally and more broadly. Latter reason first: rare is the individual who, like me (or most-to-all of you), can a) diagnose the issue and b) is even aware of Google Public DNS (or OpenDNS or another alternative) as a fix, far from c) being able to implement the fix. Online discussion traffic on the issue suggests that Comcast and Microsoft's technical support personnel do little but point the blame finger at each other when an affected individual contacts either company. I wonder how many Xbox LIVE account holders are currently unable to go online because of it? And how much business both Comcast and Microsoft have lost as a result?

Personally, I'm also frustrated, because when they work, Comcast's DNS servers work well. Here are the results of a recent NameBench benchmark test that I ran, which automatically tests the performance of various DNS server alternatives:


Mean Response Duration


Fastest Individual Response Duration


Response Distribution Chart (First 200ms)


Response Distribution Chart (Full)

As you can see, Comcast's DNS servers are notably faster than Google Public DNS ... which is faster than the others, so I at least chose well when picking an alternative. Truth be told, I haven't noticed any real-life speed degradation when web browsing, accessing email, etc so I'm not particularly concerned about the transition from a performance standpoint. But there's one other concern, which has me less sanguine. I already share a lot of information with Google via the various services that I regularly use; Gmail, Google Drive, Google Reader (until recently, that is), the company's search engine, etc. Google Public DNS gives the company yet another means of learning more about me than I'm innately comfortable with.

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