"no data known" vrs "host not found"

[Barry Finkel]

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