My day job has had some interesting discussions lately about TCP to the root servers based on a few odd behaviors we've had reported to us over the past few years. There aren't any surprises in this data, it's been known for a long time some people think DNS is UDP only for instance, some firewalls are broken, and so on. What we realized though is that there is no wide-spread measurement of how often TCP is a problem. Immediately my thought went to the Atlas probe network. It's distributed enough it could give an interesting indication of how often TCP DNS fails compared to UDP DNS. Perhaps the rates are so similar it's a non-issue, perhaps TCP fails much more often. Would it be of interest to the Atlas community to have the probes try and query "." via both UDP and TDP from each of the 13 root servers (perhaps v4 and v6 separately), report back that data, and then generate a report on the results? I would be happy to assist in preparing or presenting a report on the results! -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/