$HOME/.ssh/authorized_keys2、authorized_keys に変えた方が良い。 OpenSSH 3.0 の時点で既に obsolete 扱いですし、ver.up で authorized_keys2 を読まなくなったとしても、もはや文句言えないと思う。
http://www.openssh.com/txt/release-3.0> 2) The files /etc/ssh_known_hosts2 ~/.ssh/known_hosts2 ~/.ssh/authorized_keys2 are now obsolete, you can use /etc/ssh_known_hosts ~/.ssh/known_hosts ~/.ssh/authorized_keys For backward compatibility ~/.ssh/authorized_keys2 will still used for authentication and hostkeys are still read from the known_hosts2. However, those deprecated files are considered 'readonly'. Future releases are likely not to read these files. << 不確かですが、PuTTY も authorized_keys2 は読まなくなってた記憶あります。
