Problems with DNS

[perikillo]

   HI all.

     I have one freebsd box running 5.3, i get my IP from one internal
DHCP running NT 4.0, here we have one PDC on NT 4.0, to get to the
outside we pass thru one http proxy and one firewall, i have my user
and password for the proxy, i want to get outside, i install manually
the cvsup program, i download that one from another machine and burn
the file on that machine because i cannot made my freebsd box reach
internet.

     I already setup this variables:

     /root/.cshrc
    setenv HTTP_PROXY http://myuser:mypass@192.168.1.2:3128
    setenv FTP_PROXY http://myuser:mypass@192.168.1.2:3128

     /etc/make.conf

    FETCH_ENV= HTTP_PROXY=http://myuser:mypass@192.168.1.2:8080
    FETCH_ENV= FTP_PROXY=http://myuser:mypass@192.168.1.2:8080

    i have my NIC setup on /etc/rc.conf to get the IP from my DHCP
server, and found my lease on /var/db/dhcp.lease

    There i see my info, my domain, i create my /etc/resolv.conf and
input my domain:

nameserver     MYDOMAIN   <----My lease have this 

    But went i run cvsup, say that it cannot resolved hostname, i
really dont know what more to do, i read the handbook, but dont find
any good info on the DHCP setup, only talk about the server but not
about how to setup the client, only say some files, dhcp.conf, etc.

   I need to setup those files...?

   I dont have any packages install, because i cannot reach Internet,
i was thinking this was simply, but i dont know what iam doing wrong,
some tips about my problem...?