Appendix A. OpenSSH 4.0 New Features

Stop the presses! Just before this book was printed, OpenSSH 4.0 was released by those fine folks at openssh.com. While compatible with Version 3.9, it has several important new features that we discuss briefly. (We cover just features, not bug fixes.)

Server Features: sshd

The OpenSSH server has new features pertaining to logging, listening addresses, and password and account expiration warnings.

When authentication attempts are rejected by user-level access control (AllowUsers, DenyUsers) or group-level access control (AllowGroups, DenyGroups), sshd will log an informative message about it.

The AddressFamily configuration keyword, previously available to clients only, can now be configured for the SSH server as well. If your server supports both IPv4 and IPv6, this lets you control on which sort of addresses sshd will listen.

If your password or account is going to expire (on operating systems that support expiration), sshd will now warn you in advance when you authenticate—for example.:

    Your password will expire in 6 days
    Your account will expire in 11 days