Ned Slider a écrit : > Choose a random unused high port number (above 1023) > > http://www.iana.org/assignments/port-numbers. > >> 2) How do I configure these different ports ? By that, I mean : how do I >> tell SSH to use them instead of port 22 ? >> > > http://wiki.centos.org/HowTos/Network/SecuringSSH#head-3579222198adaf43a3ecbdc438ebce74da40d8ec Thanks, that helped. I sort of managed to configure different SSH ports for the two machines. Now I'm facing another quite unexpected problem. Let me try to describe what's going on. Machine number 1 (bernadette) is 192.168.1.2. I reconfigured SSH on this machine to use port 10022. Machine number 2 (raymonde) is 192.168.1.3. SSH port on raymonde is 10023. I took care of reconfiguring the firewall and open the respective ports (10022:tcp on bernadette, 10023:tcp on raymonde). In my router's web interface (Expert Mode > NAT) I defined a port redirection, so that requests for port 10022 are rerouted to 192.168.1.2, and requests for port 10023 to 192.168.1.3. Now I can ssh into my two machines from the outside, using my public IP address. E. g. : # ssh my.ip.add.res -p 10022 --> I'm logged into bernadette # ssh my.ip.add.res -p 10023 --> Logs me into raymonde Except... when logging in a second time, in the other machine, I get this, understandably : @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. Now, of course, I could manually open ~/.ssh/known_hosts, erase the respective line and then log back again. But is there a more orthodox way to log into two different machines via two distinct ports on one single IP address without getting this sort of error ? Cheers, Niki