DNS Problems

Why does my window machine fail to reach or query a nameserver?

When I do the nslookup from the ms-dos prompt to the nameserver I get a rather quick 2 second timeout and the query fails.

When I use online services there is no problem reaching the domain name server.

I had another domain which was using the domain server to reference http services at a host. This domain is of course un reachable by me but for the most part the website has received a good amount of traffic even though I cannot reach it myself.

How do I know what's happening? Has somebody physically blocked the lookup from my machine? Or is there some sort of poisoning happening. Any suggestions as to what I can do to better understand the exact nature of the problem would be appreciated.

If I perform a traceroute from the domain name server which I suspect is failing I see the correct server at the bottom of the list.

; <<>> DiG 9.3.2 <<>> @ns5.ivcdns.com ishopathome.ca A +trace
 ; (1 server found)
 ;; global options:  printcmd
 .			385788	IN	NS	D.ROOT-SERVERS.NET.
 .			385788	IN	NS	E.ROOT-SERVERS.NET.
 .			385788	IN	NS	F.ROOT-SERVERS.NET.
 .			385788	IN	NS	G.ROOT-SERVERS.NET.
 .			385788	IN	NS	H.ROOT-SERVERS.NET.
 .			385788	IN	NS	I.ROOT-SERVERS.NET.
 .			385788	IN	NS	J.ROOT-SERVERS.NET.
 .			385788	IN	NS	K.ROOT-SERVERS.NET.
 .			385788	IN	NS	L.ROOT-SERVERS.NET.
 .			385788	IN	NS	M.ROOT-SERVERS.NET.
 .			385788	IN	NS	A.ROOT-SERVERS.NET.
 .			385788	IN	NS	B.ROOT-SERVERS.NET.
 .			385788	IN	NS	C.ROOT-SERVERS.NET.
 ;; Received 500 bytes from 66.98.135.161#53(66.98.135.161) in 132 ms
 
 ca.			172800	IN	NS	CA01.CIRA.ca.
 ca.			172800	IN	NS	CA05.CIRA.ca.
 ca.			172800	IN	NS	CA06.CIRA.ca.
 ca.			172800	IN	NS	TLD3.ULTRADNS.ORG.
 ca.			172800	IN	NS	NS-EXT.ISC.ORG.
 ca.			172800	IN	NS	CA03.CIRA.ca.
 ca.			172800	IN	NS	CA02.CIRA.ca.
 ca.			172800	IN	NS	CA04.CIRA.ca.
 ca.			172800	IN	NS	TLD2.ULTRADNS.NET.
 ca.			172800	IN	NS	TLD1.ULTRADNS.NET.
 ;; Received 473 bytes from 128.8.10.90#53(D.ROOT-SERVERS.NET) in 119 ms
 
 ishopathome.ca.		86400	IN	NS	ns2.sitebyjames.com.
 ishopathome.ca.		86400	IN	NS	ns1.sitebyjames.com.
 ;; Received 83 bytes from 192.228.27.11#53(CA01.CIRA.ca) in 114 ms
 
 ishopathome.ca.		14400	IN	A	76.74.187.43
 ishopathome.ca.		86400	IN	NS	ns2.sitebyjames.com.
 ishopathome.ca.		86400	IN	NS	ns1.sitebyjames.com.
 ;; Received 131 bytes from 76.74.187.13#53(ns2.sitebyjames.com) in 186 ms

ns1.sitebyjames.com is my nameserver and it's serving the correct IP...

But... If I just do a straight query on the domain I get a SERVFAIL...

 ; <<>> DiG 9.3.2 <<ns5>>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 26302
 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
 
 ;; QUESTION SECTION:
 ;ishopathome.ca.			IN	A
 
 ;; Query time: 132 msec
 ;; SERVER: 66.98.135.161#53(66.98.135.161)
 ;; WHEN: Wed Nov 12 06:29:23 2008
 ;; MSG SIZE  rcvd: 32

What's happening?

I assume someone has not set up a thier nameserver correctly and they made the mistake of instructing the move to the ns5.ivcdns.com nameserver. However this still does not explain why I cannot physically reach that nameserver from my own machine.