How can you be so sure it's connection problem when the OP hasn't even posted anything new? I was giving another option since it happened to me once. I've set the IP for both end, and before I even try to SSH to N900, I tried pinging but to fail. Turns out the N900 doesn't answer to ICMP request since I can just SSH to it perfectly. Also if my memory serves well, I believe FTP server and SSH server are not installed by default on N900. So if the OP hasn't installed them, then it's not going to work either. If SSH/FTP server isn't working, even if your TCPIP is working, by the end it isn't going to work either.