We had a very long unexpected downtime today due to both our DNS servers crashing. The servers started working again at about 4:30pm CET, when exactly they went down is unclear (but before 10am). This failure made our jabber service effectively unreachable to our users. Interestingly, there never where fewer than 17 users online, those users must have had our IP in their hosts file. We used the opportunity to switch from our flaky DNS servers to the ones provided by Nessus which already has been our registrar so far. We apologize for the downtime and hope there will never be a downtime due to failing DNS servers again.