sshd_config(5) (r1.23) says: LoginGraceTime The server disconnects after this time if the user has not successfully logged in. If the value is 0, there is no time limit. The default is 120 seconds but the default /etc/ssh/sshd_config overwrites it to 600 seconds.
However, the corresponding part in /etc/sshd_config (r1.17) is: 39 # Authentication: 40 41 #LoginGraceTime 2m This non-standard default value of 600s is introduced to sshd_config r1.2 probably as a workaround for slow machines that cannot establish authentication within 120s: http://cvsweb.netbsd.org/bsdweb.cgi/src/crypto/external/bsd/openssh/dist/sshd_config#rev1.2 But it was removed in r1.14 when OpenSSH 6.8 was imported. I don't know whether it is intentional or unintentional. http://cvsweb.netbsd.org/bsdweb.cgi/src/crypto/external/bsd/openssh/dist/sshd_config#rev1.14 The question is which one, sshd_config or manpage, should be corrected. IMO, timeout of 600s is still useful for CPUs like i486 or MC68030. Thanks, rin