I've choose Ubuntu 16.04 LTS as main OS on my production servers. It has the latest version of Linux kernel, frequent updates and seems to be stable.
However 2 days I can not resolve the problem with sshd service. In general it works good. The problems appears after system reboot. I'm able to login via SSH, but systemd says that sshd.service is not runnning / failed to start. Also I can not restart sshd service and I see the same error.
● ssh.service - OpenBSD Secure Shell server Loaded: loaded (/lib/systemd/system/ssh.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Sat 2017-03-11 12:17:42 UTC; 37s ago Process: 3535 ExecStart=/usr/sbin/sshd -D $SSHD_OPTS (code=exited, status=255) Main PID: 3535 (code=exited, status=255) Mar 11 12:17:42 node2 systemd: Starting OpenBSD Secure Shell server... Mar 11 12:17:42 node2 sshd: error: Bind to port 22 on 0.0.0.0 failed: Address already in use. Mar 11 12:17:42 node2 sshd: fatal: Cannot bind any address. Mar 11 12:17:42 node2 systemd: ssh.service: Main process exited, code=exited, status=255/n/a Mar 11 12:17:42 node2 systemd: Failed to start OpenBSD Secure Shell server. Mar 11 12:17:42 node2 systemd: ssh.service: Unit entered failed state. Mar 11 12:17:42 node2 systemd: ssh.service: Failed with result 'exit-code'.
I've reinstalled Ubuntu 16.04 LTS on server many times and tried to change sshd_config file as well to fix this. However it does not help. Here is my sshd_config:
# Package generated configuration file # See the sshd_config(5) manpage for details # What ports, IPs and protocols we listen for Port 22 # Use these options to restrict which interfaces/protocols sshd will bind to #ListenAddress :: ListenAddress 0.0.0.0 Protocol 2 # HostKeys for protocol version 2 HostKey /etc/ssh/ssh_host_rsa_key HostKey /etc/ssh/ssh_host_dsa_key HostKey /etc/ssh/ssh_host_ecdsa_key HostKey /etc/ssh/ssh_host_ed25519_key #Privilege Separation is turned on for security UsePrivilegeSeparation yes # Lifetime and size of ephemeral version 1 server key KeyRegenerationInterval 3600 ServerKeyBits 1024 # Logging SyslogFacility AUTH LogLevel INFO # Authentication: LoginGraceTime 120 PermitRootLogin no StrictModes yes RSAAuthentication yes PubkeyAuthentication yes #AuthorizedKeysFile %h/.ssh/authorized_keys # Don't read the user's ~/.rhosts and ~/.shosts files IgnoreRhosts yes # For this to work you will also need host keys in /etc/ssh_known_hosts RhostsRSAAuthentication no # similar for protocol version 2 HostbasedAuthentication no # Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication #IgnoreUserKnownHosts yes # To enable empty passwords, change to yes (NOT RECOMMENDED) PermitEmptyPasswords no # Change to yes to enable challenge-response passwords (beware issues with # some PAM modules and threads) ChallengeResponseAuthentication no # Change to no to disable tunnelled clear text passwords PasswordAuthentication yes # Kerberos options #KerberosAuthentication no #KerberosGetAFSToken no #KerberosOrLocalPasswd yes #KerberosTicketCleanup yes # GSSAPI options #GSSAPIAuthentication no #GSSAPICleanupCredentials yes X11Forwarding yes X11DisplayOffset 10 PrintMotd no PrintLastLog yes TCPKeepAlive yes #UseLogin no #MaxStartups 10:30:60 #Banner /etc/issue.net # Allow client to pass locale environment variables AcceptEnv LANG LC_* Subsystem sftp /usr/lib/openssh/sftp-server # Set this to 'yes' to enable PAM authentication, account processing, # and session processing. If this is enabled, PAM authentication will # be allowed through the ChallengeResponseAuthentication and # PasswordAuthentication. Depending on your PAM configuration, # PAM authentication via ChallengeResponseAuthentication may bypass # the setting of "PermitRootLogin without-password". # If you just want the PAM account and session checks to run without # PAM authentication, then enable this but set PasswordAuthentication # and ChallengeResponseAuthentication to 'no'. UsePAM yes UseDNS no GSSAPIAuthentication no
I get a lot of messages from my monitoring system about this issue. I just want to ensure that everything works properly and I will not have problems with my server in the future.
Can anybody help with this?