"no data known" vrs "host not found"

[admjcd]

Yes, its sendmail and this is from a message header:  (8.8.8/1.1.22.3/21May99-0417PM) that says the version right?

There are Two DNS servers with one set up as a backup. I am actually the mail person and run our Exchange servers but our DNS peolple handle the sendmail server. They do not like that I am pressing this issue, but the customers call me when the mail fails.

Also I did some research on "negative Caching" and found this :

http://www.faqs.org/rfcs/rfc2308.html

   "Negative responses without SOA records SHOULD NOT be cached as there
   is no way to prevent the negative responses looping forever between a
   pair of servers even with a short TTL.

   Despite the DNS forming a tree of servers, with various mis-
   configurations it is possible to form a loop in the query graph, e.g.
   two servers listing each other as forwarders, various lame server
   configurations.  Without a TTL count down a cache negative response

   when received by the next server would have its TTL reset.  This
   negative indication could then live forever circulating between the
   servers involved."


  
  

-----Original Message-----
From: Barry Finkel [mailto:b19141 at achilles.ctd.anl.gov] 
Sent: Monday, March 25, 2002 12:49 PM
To: bind-users at isc.org
Cc: admjcd at volpe.dot.gov
Subject: Re: "no data known" vrs "host not found"


In article <a7g931$kmf at pub3.rc.vix.com>, admjcd  <admjcd at VOLPE.DOT.GOV> wrote:
>>When ever we send mail we get back these NDRs when ever the domain is
>>not correct. Sometimes we get them when the domain is correct. Both 
>>types are "host unknown".  One says  "no data known" and the others 
>>say "host not found" .  What is the difference between these two and 
>>why should we get the "no data known" intermittenly message when the 
>>domain does exist?

Barry Margolin <barmar at genuity.net> replied:

>Something very weird is going on with the army.mil entries that result
>in "no data known" messages.  They have MX records, but if you perform 
>an ANY query (as sendmail does), the MX record appears in the Authority 
>section instead of the Answer section.  And its TTL decreases on each 
>query, implying that the MX record is in the cache, not the 
>authoritative data for the zone.  You should probably let the Army 
>hostmaster know that there's a problem with their server.

I have seen this problem with the Army's DNS for a long time (Dec 2000). I even posted the problem here May 30, 2001.  I have not gotten a reply from army.mil since my initial queries in 2000, and obviously the problem has not been corrected.
----------------------------------------------------------------------
Barry S. Finkel
Electronics and Computing Technologies Division
Argonne National Laboratory          Phone:    +1 (630) 252-7277
9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
Building 222, Room D209              Internet: BSFinkel at anl.gov
Argonne, IL   60439-4828             IBMMAIL:  I1004994