When resolving FQDNs or machine names to IP addresses on my local network (mycompany.internal) I can use dig on the command line (linux/mac) or nslookup (windows) to query the configured server and get a response. But trying to enter the FQDN or even just the machine name in a ping command or in a web browser results in 'Unknown Host' or DNS errors. Here's a sample, this one from the Mac:

mac:~ atroon$ dig server.mycompany.internal


; <<>> DiG 9.6.0-APPLE-P2 <<>>
server.mycompany.internal ;; global
options: +cmd ;; Got answer: ;;
->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5219 ;; flags: qr aa rd
ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0,
ADDITIONAL: 0

;; QUESTION SECTION:
;server.mycompany.internal.  IN A

;; ANSWER SECTION:
server.mycompany.internal. 1200 IN A 172.16.254.36

;; Query time: 0 msec ;; SERVER:
172.16.254.8#53(172.16.254.8) ;; WHEN: Wed Dec 16 11:39:15 2009 ;; MSG SIZE 
rcvd: 55

mac:~ atroon$ ping server.mycompany.internal<br>
ping: cannot resolve server.mycompany.internal: Unknown host

I cannot for the life of me figure this one out. The DNS server is a SBS 2003 box which handles AD, some file/print, etc for a small company network. This issue happens to me about three times a week, and when I'm connected to the local network directly, the same switch as the server even. I can make any connection I want with IP addresses, I just can't make DNS work. Additionally, at the same time I'm experiencing this, other users are fine, which makes me think it's a problem on my Mac. But what sort of problem? How can dig send a query and get a reply, and ping say 'unknown host'?

I'm posting here vs. serverfault because I think this is a local problem not a server problem...but if anyone can point me at the server, I guess we'll head down the street a domain or two.