rscott13 - 8:18 pm on Sep 1, 2011 (gmt 0)
For those that have not heard, GoDaddy has a new policy (as of July, 2011) that lets them block DNS packets from high-volume DNS servers. Any domains using GoDaddy's DNS hosting are affected (any domains with 'domaincontrol.com' in them).
Two such sites that are affected include a niche search engine that is in development, and a project that keeps track of statistics on domains. Sites like these that are blocked by GoDaddy's new policy will be unable to include domains using GoDaddy's DNS hosting (except domains owned by GoDaddy, which are exempt from the Selective DNS Blackouts policy).
So keep this in mind if there is some odd glitch with your domain. For example, if they block the DNS servers of a company that sends an extreme amount of E-mail, any E-mails to domains using GoDaddy DNS hosting will not be delivered. Or, if in general just about everyone can reach your website without problems, but now people from a specific country or using the same Internet provider cannot reach your site, this could explain it.
Also, if you run a DNS server that does a high volume of lookups (other than a standard recursive DNS server), and you experience a lot of DNS failures, you should check to see if packets sent to the 18.104.22.168/26 or 22.214.171.124/26 IP ranges are blocked.