Disappearing DNS Servers
I had prepared a draft blog about Version 6.0.6278.27 of the DNS MP (14/8/2008). It is very noisy but having installed it in a couple of environments and read through the MP guide I think I had a handle on how to tune it. But rather than publish that I am posting this instead.
I am about to remove that MP from the environments that I have installed it in and replace it with the old version. The reason being is that the DNS servers seem to disappear from the discovered DNS servers list and sometimes come back but generally not. I picked up this from the newsgroup and initially I did not see that problem but then it happened to me and a few other people have replied that it has happened to them as well. So it does not matter how much better the new MP is (or not depending on how you view noisy MPs) but if it is not running the rules on the servers it is supposed to then there is no point in deploying it.
I did turn on the trace and watched the events come in and looked at the script to see how the script was working. And for non DNS servers the discovery failed and exited which is fine. For DNS servers they all exited OK but only some of them had the event to say they were putting in discovery data and that matched the list showing in the console. There appears to be no rhyme or reason why some DNS servers put the data in and some do not and looking at the script it is not obvious why this is happening. There was a report that upgrading to .Net 3.5 sorted it out but I had some servers on that version that were in the discovered list and some that were not. So far no response from Microsoft on this but it is difficult to recreate as my servers were all discovered for a few weeks before some of them disappeared. Very strange. If you are running this MP it is worth checking that it has found all your DNS servers.