Should be in /etc/resolv.conf (at least on debian it is). ( err, I skipped reading the part where you said it's not there [/edit]) If not check the output of dig some.server.com
demian@dirac: ~ $ dig www.google.com
[lotsa stuff here]
;; Query time: 25 msec
;; SERVER: 184.108.40.206#53(220.127.116.11) # <- There's the server that answerd!!!
;; WHEN: Wed Jun 23 00:10:06 2004
;; MSG SIZE rcvd: 99