> ssh nicolas@localhost Password: Linux hipparchia 2.4.27-2-686-smp #1 SMP Wed Nov 30 21:47:06 JST 2005 i686 GNU/Linux The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. No mail. Last login: Thu Feb 9 13:31:58 2006 from *.*.jussieu.fr $ exit logout Connection to localhost closed. > ssh nicolas@127.0.0.1 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ 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. The fingerprint for the RSA key sent by the remote host is ******************************. Please contact your system administrator. Add correct host key in /home/nicolas/.ssh/known_hosts to get rid of this message. Offending key in /home/nicolas/.ssh/known_hosts:1 RSA host key for 127.0.0.1 has changed and you have requested strict checking. Host key verification failed.
Citation
man sshd
Specifies a file from which a host key is read. This option must be given if sshd is not run as root (as the normal host key files are normally not readable by anyone but root). The default is /etc/ssh/ssh_host_key for protocol version 1, and /etc/ssh/ssh_host_rsa_key and /etc/ssh/ssh_host_dsa_key for protocol version 2. It is possible to have multiple host key files for the different protocol versions and host key algorithms.