DNS queries for . IN A return rcode 2 SERVFAIL from windows DNS recursing resolvers

Joe Maimon jmaimon at ttec.com
Tue Jan 5 07:20:45 CST 2010


Hey all,

This must be old news for everyone else. While looking at a dns monitor 
on a load balancer that defaulted to . A queries to check liveliness on 
DNS resolvers, it became quite clear that windows 2000/2003 DNS server 
appears to return rcode=2 for queries looking for an A record for the 
root. The resolvers appear to work properly in all other regards.

So the monitors were switched to localhost. A

(Is this a bad idea?)

A little testing later and the results for . A are:

Windows NT 4, ancount=0, authority=1, rcode=0
Windows 2000, rcode=2
Windows 2003, rcode=2
bind, ancount=0, authority=1, rcode=0

To my (inexpert) eyes that doesnt seem quite right.

I cant seem to find any online information regarding this difference of 
behavior.

Enlightenment appreciated.

Joe



Here is the output.

fpdns -c -s 64.95.32.34 && dig @64.95.32.34 . a
64.95.32.34     Microsoft Windows DNS NT4

; <<>> DiG 9.6.1-P2 <<>> @64.95.32.34 . a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35180
;; flags: qr aa; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;.                              IN      A

;; AUTHORITY SECTION:
.                       86400   IN      SOA     A.ROOT-SERVERS.NET. 
NSTLD.VERISIGN-GRS.COM. 2010010500 1800 900 604800 86400

;; Query time: 114 msec
;; SERVER: 64.95.32.34#53(64.95.32.34)
;; WHEN: Tue Jan  5 07:40:33 2010
;; MSG SIZE  rcvd: 92


fpdns -c -s 216.222.144.16 && dig @216.222.144.16 . a
216.222.144.16  ISC BIND 9.2.3rc1 -- 9.6.1-P1 [recursion enabled]  id: 
"9.5.1-P2"

; <<>> DiG 9.6.1-P2 <<>> @216.222.144.16 . a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49220
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;.                              IN      A

;; AUTHORITY SECTION:
.                       2314    IN      SOA     A.ROOT-SERVERS.NET. 
NSTLD.VERISIGN-GRS.COM. 2010010500 1800 900 604800 86400

;; Query time: 38 msec
;; SERVER: 216.222.144.16#53(216.222.144.16)
;; WHEN: Tue Jan  5 07:42:08 2010
;; MSG SIZE  rcvd: 92

fpdns -c -s joe.jmaimon.com && dig @joe.jmaimon.com . a
216.222.150.100 ISC BIND 9.2.3rc1 -- 9.6.1-P1 [recursion enabled]  id: 
"9.5.0-P2-W2"

; <<>> DiG 9.6.1-P2 <<>> @joe.jmaimon.com . a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39125
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;.                              IN      A

;; AUTHORITY SECTION:
.                       10800   IN      SOA     A.ROOT-SERVERS.NET. 
NSTLD.VERISIGN-GRS.COM. 2010010500 1800 900 604800 86400

;; Query time: 40 msec
;; SERVER: 216.222.150.100#53(216.222.150.100)
;; WHEN: Tue Jan  5 07:57:52 2010
;; MSG SIZE  rcvd: 92


  fpdns -c -s 64.95.32.130 && dig @64.95.32.130 . a
64.95.32.130    Microsoft Windows DNS 2000

; <<>> DiG 9.6.1-P2 <<>> @64.95.32.130 . a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 30535
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;.                              IN      A

;; Query time: 35 msec
;; SERVER: 64.95.32.130#53(64.95.32.130)
;; WHEN: Tue Jan  5 07:43:51 2010
;; MSG SIZE  rcvd: 17


  fpdns -c -s 72.26.241.205 && dig @72.26.241.205 . a
72.26.241.205   No match found

; <<>> DiG 9.6.1-P1 <<>> @72.26.241.205 . a
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 12807
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;.                              IN      A

;; Query time: 0 msec
;; SERVER: 72.26.241.205#53(72.26.241.205)
;; WHEN: Tue Jan  5 08:13:06 2010
;; MSG SIZE  rcvd: 17









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