CNAME Issue - Whether to use CNAME-data or Response-Flag

[Steven Wilmot]

See inline replies below...

-----Original Message-----
From: David Forrest [mailto:drf at maple.maplepark.com] 
Sent: 09 April 2010 7:53 PM
To: Steven Wilmot
Cc: bind-users at lists.isc.org
Subject: Re: CNAME Issue - Whether to use CNAME-data or Response-Flag

>>>> On Fri, 9 Apr 2010, Steven Wilmot wrote:
>>>> [...]

>> Steven, your analysis reflects that your client requested that recursion
was not desired in your query 
>>   (.... ...0 .... .... = Recursion desired: Don't do query recursively). 
>> When I queried my ISP (dnsr1.sbcglobal.net.) recursively, I received the
following:
>> [root at maple ~]# host  mail.wilmot.me.uk. dnsr1.sbcglobal.net.
>> Using domain server:
>> Name: dnsr1.sbcglobal.net.
>> Address: 68.94.156.1#53
>> Aliases:

>> mail.wilmot.me.uk is an alias for wilmot.me.uk.mail.aaisp.net.uk.
>> wilmot.me.uk.mail.aaisp.net.uk has address 81.187.30.19
wilmot.me.uk.mail.aaisp.net.uk has IPv6 address
2001:8b0:0:30:230:48ff:fedb:25dc

This is the result that I would expect (and also the result that ANY version
of BIND seems to successfully resolve.

Basically, you are using your own ISP's server (dnsr1.sbcglobal.net.) which
is receiving the following message from 'primary-dns.co.uk'
  "mail.wilmot.me.uk is an alias for wilmot.me.uk.mail.aaisp.net.uk."

And THEN it is successfully looking up this value (at the nameservers for
aaisp.net.uk) at getting the right result

---

>> and when I turned off recursion, I got this: [...]

>> I get a NXDOMAIN in both cases.  
>> Maybe because I'm outside your ISP's network, but I do NOT expect a
NXDOMAIN response as:
>> "NXDOMAIN or Non-Existent Domain is a term used for the Internet domain
name that is unable to be resolved using the DNS implementation owing either
to domain name not yet registered or the server problem.

>> The reference to the NXDOMAIN is published in RFC 1035 (Domain names -
implementation and specification) 
>> and also in RFC 2308 (Negative Caching of DNS Queries or referred to as
DNS NCACHE)"

--- 

Basically, this whole issue is based on the premise that "BIND is working as
expected", but "Microsoft DNS server is NOT working as I would expect" (but
I am not a dns-expert.

The problem that I am trying to solve is the following

ONE of the following This leads to one of two conclusions:

EITHER: 
* The server "primary-dns.co.uk" is NOT responding with a valid record in
the first place.

OR:
* The Microsoft DNS Server is at fault by NOT responding to this correctly.

I currently have this open as an active support-issue with Microsoft, but
decided to ask for extra opinions in this BIND forum.

---

>> Caveats: 
>> * I'm using isc BIND 9.7.0-P1.  YMMV
>> * I'm somewhat clueless.

>>> Dave

Thanks... Appreciate the thoughts (and the pointers to the two DNS RFCs) but
I'm still not quite sure where (if at all) the "problem" lies.

Regards, 

Steven Wilmot 
Director 
Data Utilities Ltd