Question : Domain Controller - RPC server is unavailable

So its Friday night around 5 pm and I m getting ready to head home and our DC locks up and I restart it 3 times. We have lost outside internet access and the DC is no longer available to the network! Everything else is working fine, I have setup an additional DC as a backup, but its not working like its supposed to, cuz we still dont have outside access, but I think its running the rest of the network because everything else is communicating with each other.

One of the things I noticed was that the c:\ drive is a 4 gig partition and its only got 7% free space. the other side of that partition has 63gigs available.

I can not ping any address on the network from the DC but on other computers i can ping our router/firewall/other machines. When I try to manualy replicate I get the following error :

 The RPC server is unavailable. This condition may be caused by a DNS lookup problem.

I double checked that the RPC service was running, and it is, I also typed in : NET START RPCSS to verify it was running, it was.

This is a windows 2000 server running DNS.

Answer : Domain Controller - RPC server is unavailable

have you tried turning off offline mode?  If the DNS is not correct, that could also cause the problem.  Here is how to setup your DNS (replace the server names and IPs with your own):

DC IPs
server1: 192.168.1.10
server2: 192.168.1.11

DNS config:
Server1:  Point DNS to 192.168.1.11 only (second entry blank)
Server2:  Point DNS to 192.168.1.10 only (second entry blank)
All other servers/workstations:  192.168.1.10 primary, 192.168.1.11 secondary