Here is the problem, which started a few days ago.
A windows 2003 domain has 9 subnets, 2 DC's.
MOST of the servers are in Subnet A, which so far is reachable from the other subnets except for one, subnet T for Trouble.
There is a secondary DC in subnet B, which is also reachable.
3 servers, including the remote licensing server, are in subnet T and cannot be reached from anywhere, even from within the same subnet. Error logs say no domain controller is available, or the time server cannot be reached.
So far people can logon to the network, but people can no longer use RDS on the server in subnet A because (I think) the remote licensing server which is in subnet T, is out of reach. Error is Access Denied. RDS was working this morning.
I also cannot remote to other servers, except the DC, in subnet A- getting the error "there are no logon servers to access the request" strange because the DC's are both running, Exchange is running.
I can ping, access shares in subnet A from subnet T, but not vice versa.
NSlookup gives correct results from a server in subnet A, but times out in 2 seconds and says server unknown from subnet T. There are PTR records for the DCs in the correct places, but any advice on this is welcome.
I seems like there is no route to subnet T from subnet A, but I don't control the SonicWall firewall. I am attaching a document with the domain firewall policy and a script I recently applied to the workstations ONLY, to make Lansweeper work. I did not apply it to the servers because they were being scanned ok. Before I go back to the people managing the routing, I would appreciate any help I can get on this.