HE.net DNS problems
Hurricane Electric had a significant outage of their authoritative DNS servers this morning, causing them to return valid responses with no results for all(?) queries. This will have caused delivery problems for any mail going to domains using HE.net DNS – which will include some of their colocation customers, as well as users of their free services – but also will have caused reverse DNS to fail for most servers hosted by Hurricane Electric worldwide, so if any of your mail is being sent from HE hosted machines you may have seen problems.
(We’re HE customers so we noticed. Still happy with them as a vendor.)