DNS Caching Issue

[Lyle Giese]

On 07/25/11 09:22, Sathyan Arjunan (sarjunan) [CONTRACTOR] wrote:
> Recent days, I am facing frequent caching issues with my DNS servers
> which are responsible for recursive lookup to external queries. As a
> temporary solution, we used to refresh the named daemon to clear the
> cache. To isolate this issue we upgraded the BIND to “BIND 9.7.3” but
> even after the upgrade issue repeats.
>
> If I do a nslookup for “*mail.sin.gpi-g.com*”, it fails.
>
> *nslookup mail.sin.gpi-g.com**
> *Server: dnsserver
>
> Address: x.x.x.x#53
>
> *** server can't find mail.sin.gpi-g.com: SERVFAIL*
>
> To fix this I have to restart the named daemon in caching DNS server.
> Once I restart, the lookup resolves well. However the issue appears
> again in few days. Any thoughts?
>
> nslookup mail.sin.gpi-g.com
>
> Server: dnsserver
>
> Address: x.x.x.x#53
>
> Non-authoritative answer:
>
> Name: mail.sin.gpi-g.com
>
> Address: 203.175.163.180
>
> Regards,
>
> --Sathyan
>

Simple ask both nameservers for the domain sin.gpi-g.com and you get 
different answers.  They have serious DNS problems.

Lyle Giese
LCR Computer Services, Inc.


dig @192.5.6.30 sin.gpi-g.com

; <<>> DiG 9.7.3 <<>> @192.5.6.30 sin.gpi-g.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24506
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;sin.gpi-g.com.                 IN      A

;; AUTHORITY SECTION:
gpi-g.com.              172800  IN      NS      nameserver1.gpi-g.com.
gpi-g.com.              172800  IN      NS      nameserver2.gpi-g.com.

;; ADDITIONAL SECTION:
nameserver1.gpi-g.com.  172800  IN      A       202.169.51.115
nameserver2.gpi-g.com.  172800  IN      A       202.182.61.51

;; Query time: 95 msec
;; SERVER: 192.5.6.30#53(192.5.6.30)
;; WHEN: Mon Jul 25 19:15:22 2011
;; MSG SIZE  rcvd: 115

  dig @202.169.51.115 mail.sin.gpi-g.com

; <<>> DiG 9.7.3 <<>> @202.169.51.115 mail.sin.gpi-g.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 6393
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;mail.sin.gpi-g.com.            IN      A

;; ANSWER SECTION:
mail.sin.gpi-g.com.     38400   IN      A       203.175.163.180

;; AUTHORITY SECTION:
sin.gpi-g.com.          38400   IN      NS      nameserver2.gpi-g.com.

;; ADDITIONAL SECTION:
nameserver2.gpi-g.com.  14400   IN      A       202.182.61.51

;; Query time: 300 msec
;; SERVER: 202.169.51.115#53(202.169.51.115)
;; WHEN: Mon Jul 25 19:15:48 2011
;; MSG SIZE  rcvd: 94

dig @202.182.61.51 mail.sin.gpi-g.com

; <<>> DiG 9.7.3 <<>> @202.182.61.51 mail.sin.gpi-g.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 3923
;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;mail.sin.gpi-g.com.            IN      A

;; Query time: 301 msec
;; SERVER: 202.182.61.51#53(202.182.61.51)
;; WHEN: Mon Jul 25 19:16:02 2011
;; MSG SIZE  rcvd: 36