I don't know if this is the right place, but it is a place to start. I have two machines in a co-location facility. They are both on the same physical network segement and have real internet addresses and RFC1918 addresses. We get charged for traffic which goes across the "real" internet addresses which is part of the purpose for the RFC1918 network. The problem is connecting the UNIX machine to the NT machine. If I use the RFC1918 address NT responds with a "connection refused" If I connect using the real internet address I can connect with SMBCLIENT but I cannot use SMBMOUNT (I get Invalid Argument). it is important that we use the RFC1918 address becuase we use that network to backup the NT machine on to the UNIX machine. The UNIX machine is: Linux 2.0.32 with SMP support running on an Intel machine. The NT machine is NT 4.0 w/ SP3 running on an Intel machine. Any ideas are appreciated... Cheers, Steve