DNS problem at bt.co.uk

[Barry Margolin]

In article <a4bj47$2f0 at pub3.rc.vix.com>,
Jim Hatfield  <jim.hatfield at insignia.com> wrote:
>
>I wonder if someone more expert in DNS than me can help.
>
>I'm trying to send mail to someone at bt.com. All the MX
>records point to machines like mailhub1.axion.bt.co.uk.
>However I can't resolve any of their IP addresses.
>
>It looks like a glue record problem in that the nameservers
>for bt.co.uk are:
>
>>;; ANSWER SECTION:
>>bt.co.uk.               2h41m36s IN NS  ns0.bt.net.
>>bt.co.uk.               2h41m36s IN NS  dns0.AXION.bt.co.uk.
>
>and if I ask for that I get the glue record:
>
>>;; ADDITIONAL SECTION:
>>ns0.bt.net.             1d8h53m10s IN A  194.72.6.51
>
>but if I ask ns0.bt.net for the ns records for axion.bt.co.uk I get:

Don't ask it for the NS records, ask it for the A record for
dns0.axion.bt.co.uk (since that's what a real nameserver would do).

>>;; ANSWER SECTION:
>>axion.bt.co.uk.         14h28s IN NS    DNS1.axion.bt.co.uk.
>>axion.bt.co.uk.         14h28s IN NS    dns0.axion.bt.co.uk.
>
>but there is no Additional Section. Is this a glue problem?

When I ask the right question, I get an answer with all the necessary glue:

% dig DNS0.axion.bt.co.uk. a @ns0.bt.net +norec

; <<>> DiG 8.3 <<>> DNS0.axion.bt.co.uk. a @ns0.bt.net +norec 
; (1 server found)
;; res options: init defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45677
;; flags: qr aa ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3
;; QUERY SECTION:
;;	DNS0.axion.bt.co.uk, type = A, class = IN

;; ANSWER SECTION:
DNS0.axion.bt.co.uk.	1D IN A		132.146.5.1

;; AUTHORITY SECTION:
axion.bt.co.uk.		1D IN NS	ns0.bt.net.
axion.bt.co.uk.		1D IN NS	DNS0.axion.bt.co.uk.
axion.bt.co.uk.		1D IN NS	dns1.axion.bt.co.uk.

;; ADDITIONAL SECTION:
ns0.bt.net.		1D IN A		194.72.6.51
DNS0.axion.bt.co.uk.	1D IN A		132.146.5.1
dns1.axion.bt.co.uk.	1D IN A		132.146.137.1

However, there's a problem at the higher level.  There *should* be a glue
record for dns0.axion.bt.co.uk in the .UK servers, but there isn't:

% dig DNS0.axion.bt.co.uk. a @ns1.nic.uk +norec

; <<>> DiG 8.3 <<>> DNS0.axion.bt.co.uk. a @ns1.nic.uk +norec 
; (1 server found)
;; res options: init defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6719
;; flags: qr; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 0
;; QUERY SECTION:
;;	DNS0.axion.bt.co.uk, type = A, class = IN

;; AUTHORITY SECTION:
bt.co.uk.		4H IN NS	DNS0.axion.bt.co.uk.
bt.co.uk.		4H IN NS	ns0.bt.net.

;; Total query time: 95 msec
;; FROM: tools.genuity.com to SERVER: ns1.nic.uk  195.66.240.130
;; WHEN: Tue Feb 12 13:43:36 2002
;; MSG SIZE  sent: 37  rcvd: 75

-- 
Barry Margolin, barmar at genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
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