Intermitent SERVFAIL

[Mark Andrews]

> Hi all,
>  From time to time, couple of nameservers are returning SERVFAIL when 
> querying domains hosted on one of my DNS servers. This behaviour is not 
> permanent (sometimes it works sometimes it doesn't) and it's not linked 
> to one domain only (but all domains are hosted on my DNS server). The 
> nameservers which are giving this error are specially our ISP DNS server 
> and even bind servers which I installed.
> 
> The server which hosts the domains is using bind9 on FC1. To give you an 
> example try dig www.infolitoral.ro and see if it works from your NS and 
> then try dig @212.93.136.2 www.infolitoral.ro to get the SERVFAIL. 
> However, doing a +trace with the last dig will resolve www.infolitoral.ro.
> 
> I really don't know how to debug this problem and localize it on my DNS 
> server or my ISP's DNS server.
> 
> Thanks for any ideas,
> Arthur

	Nameservers CANNOT be CNAMES.  They MUST be address records (A/AAAA).

	Mark

; <<>> DiG 8.3 <<>> ns1.ccina.ro @81.196.163.232 
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 63583
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 0
;; QUERY SECTION:
;;	ns1.ccina.ro, type = A, class = IN

;; ANSWER SECTION:
ns1.ccina.ro.		1D IN CNAME	backup.ccina.ro.
backup.ccina.ro.	1D IN A		81.196.163.232

;; AUTHORITY SECTION:
ccina.ro.		1D IN NS	ns.ccina.ro.
ccina.ro.		1D IN NS	ns1.ccina.ro.

;; Total query time: 376 msec
;; FROM: drugs.dv.isc.org to SERVER: 81.196.163.232
;; WHEN: Tue Mar 15 23:29:49 2005
;; MSG SIZE  sent: 30  rcvd: 98


; <<>> DiG 8.3 <<>> ns.ccina.ro @81.196.163.232 
; (1 server found)
;; res options: init recurs defnam dnsrch
;; got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6777
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 0
;; QUERY SECTION:
;;	ns.ccina.ro, type = A, class = IN

;; ANSWER SECTION:
ns.ccina.ro.		1D IN CNAME	vader.ccina.ro.
vader.ccina.ro.		1D IN A		212.93.137.210

;; AUTHORITY SECTION:
ccina.ro.		1D IN NS	ns.ccina.ro.
ccina.ro.		1D IN NS	ns1.ccina.ro.

;; Total query time: 375 msec
;; FROM: drugs.dv.isc.org to SERVER: 81.196.163.232
;; WHEN: Tue Mar 15 23:30:16 2005
;; MSG SIZE  sent: 29  rcvd: 97

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at isc.org