BIND started replying to queries for .com with .COM

[Mike Bernhardt]

I think you misunderstood me. I was getting back google.COM even when I
queried the server using nslookup from a command prompt on my Windows
desktop. The probe was failing because it is case-sensitive, but that was
the symptom, not the problem.

For example:
> google.com
Server:  athena.bart.gov
Address:  148.165.30.30

Non-authoritative answer:
Name:    google.COM
Addresses:  2607:f8b0:4005:801::200e
          172.217.3.46

Given that the problem cleared after restarting BIND on its CentOS host, I'd
say the problem was BIND.

-----Original Message-----
From: Mark Andrews [mailto:marka at isc.org] 
Sent: Tuesday, March 29, 2016 5:19 PM
To: Mike Bernhardt
Cc: bind-users at isc.org
Subject: Re: BIND started replying to queries for .com with .COM


Your monitoring probe is broken.

STD 13 says that that the DNS is case preserving.  The problem is that lots
of servers aren't case preserving instead they echo back the query case in
the owner names of records returned which named then records.

In message <030101d18a06$fa21c8d0$ee655a70$@bart.gov>, "Mike Bernhardt"
writes:
> I rebooted one of our BIND VMs this morning. It's running BIND 
> 9.10.3-P3. We noticed that queries for domains with domain.com were 
> answered with domain.COM with the .COM in capital letters. Other 
> high-levels like .org were not changed. It caused a monitoring probe 
> to complain because it wasn't getting back what it asked for.
> 
> Restarting bind on this server fixed the problem. Any ideas on what 
> happened, or where to look?
> 
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--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org