nanog mailing list archives

Re: Do I or RR need dns clue?


From: Matthew Palmer <mpalmer () hezmatt org>
Date: Fri, 17 Aug 2007 16:38:37 +1000


On Thu, Aug 16, 2007 at 10:26:35PM -0400, Tuc at T-B-O-H.NET wrote:
Tuc at T-B-O-H.NET wrote:
  Down is there isn't power to it until it gets repaired. So its not
answering period. A "nslookup" shows "timed-out". A "dig" shows 
"connection timed out; no servers could be reached" (When querying ONLY
against the down server).

  So how do I go back to RR, who told me to take it out of my 
NS records, that DNS is supposed to be silently falling back and trying
again? 


The fact that they're rejecting on a 5xx error based on no DNS PTR is a
bit harsh.  While I'm all for requiring all hosts to have valid PTR
records, there are times when transient or problem servers can cause a
DNS lookup failure or miss, etc.  If anything they should be returning a
4xx to have the remote host"try again later".

      Sorry, they aren't giving a hard fail. Its a soft fail, so we'll 
retry. But after 5 days of retrying, my servers will give up. (And, in
the mean time, the mail isn't getting through, so my users are without mail
{We store/forward for them} I don't know if the down (hard) server will be 
back that soon (Its been 2 days as is). But the whole POINT of DNS is I have 
a 2nd one listed, and they don't seem to care. They are telling me that they 
want my "primary" one back up and running.

Tell them that your primary is up and running and it's only the secondary
that's down, and see what they say.  If they disagree, ask how they know
that the server that's down is the primary...

- Matt


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