Hello, "ssh -1 [log in to unmask]" works for SSH from a Mac to a SL 4 Linux machine. However, I don't know the problem at all. If you figure out the problem, please let me know. I have to thank people who posted the messages here: http://forums.whirlpool.net.au/forum-replies-archive.cfm/549600.html Many thanks for your help, Wen