third dns server

[Stephane Bortzmeyer]

On Tue, Jun 23, 2009 at 10:31:16AM +0300,
 Mohammed Ejaz <mejaz at cyberia.net.sa> wrote 
 a message of 234 lines which said:

> We have been receiving complain by our client, during the primary
> DNS servers are down that is ns1.xyz and ns2.xyz is down. And as per
> the configuration at saudinic.net.sa (domain Registrar Company)

Sorry, but it is far from clear. Among the problems in your message,
it seems that SaudiNIC is a registry, not a registrar.

> mot.gov.sa      nameserver = ns4.mot.gov.sa (down) 

It is not down, it is misconfigured and it poisons the requesters:

% dig @ns4.mot.gov.sa. MX mot.gov.sa    
...
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 54367
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
...
;; AUTHORITY SECTION:
mot.gov.sa.		3600	IN	SOA	ns3. hostmaster. 50 900 600 86400 3600

;; Query time: 161 msec
;; SERVER: 212.119.69.222#53(212.119.69.222)
;; WHEN: Tue Jun 23 09:47:53 2009
;; MSG SIZE  rcvd: 88

For every Resource Record type, it sends zero answers (it should, for
instance, there is a MX record in the other authoritative name
servers).