Can't log in to linux

Cannot log in to linux

1. Problem description

The Linux remote server suddenly cannot log in via SSH.

Login error:

ssh_exchange_identification: read: Connection reset by peer。

2. Cause of the problem

The permissions of the var directory are incorrect

3. Solution

Change the permissions of SSH related files back to ensure that the permissions are 755 and the owner is root:root.

Here you can use the svn function of the vps server to log in to the system. The vps provider will provide the vnc login function.

3.1. Check sshd status

service sshd status

Redirecting to /bin/systemctl status sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
   Active: active (running) since 二 2019-04-09 23:36:09 CST; 18h ago
     Docs: man:sshd(8)
           man:sshd_config(5)
  Process: 1357 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 1358 (sshd)
   CGroup: /system.slice/sshd.service
           ├─ 1358 /usr/sbin/sshd
           ├─20443 sshd: root@pts/1
           ├─20445 sshd: root@notty
           ├─20447 /usr/libexec/openssh/sftp-server
           ├─20594 -bash
           ├─23794 sshd: mysql [priv]
           ├─23796 sshd: mysql@pts/0
           ├─23797 sshd: mysql [priv]
           ├─23799 sshd: mysql@notty
           ├─23800 /usr/libexec/openssh/sftp-server
           ├─23991 -bash
           ├─25381 vim /etc/init.d/mysqld
           └─25739 /bin/systemctl status sshd.service
           
4月 10 17:59:47 dap229-156 sshd[21516]: pam_unix(sshd:session): session closed for user mysql
4月 10 18:00:05 dap229-156 sshd[23794]: Accepted password for mysql from 10.43.163.30 port 54797 ssh2
4月 10 18:00:05 dap229-156 sshd[23794]: pam_unix(sshd:session): session opened for user mysql by (uid=0)
4月 10 18:00:05 dap229-156 sshd[23797]: Accepted password for mysql from 10.43.163.30 port 54798 ssh2
4月 10 18:00:05 dap229-156 sshd[23797]: pam_unix(sshd:session): session opened for user mysql by (uid=0)
4月 10 18:26:00 dap229-156 sshd[25579]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
4月 10 18:26:12 dap229-156 sshd[25580]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
4月 10 18:26:29 dap229-156 sshd[25581]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
4月 10 18:26:46 dap229-156 sshd[25590]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.
4月 10 18:30:11 dap229-156 sshd[25622]: fatal: /var/empty/sshd must be owned by root and not group or world-writable.

3.2. Repair file permissions

chmod 755 /var/empty/sshd

If the owner is wrong, you also need to modify the owner:

chown root:root /var/empty/sshd

3.3. Restart the sshd service

service sshd restart

3.4. Check the sshd status again

service sshd status

Redirecting to /bin/systemctl status sshd.service
● sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor preset: enabled)
   Active: active (running) since 三 2019-04-10 18:35:01 CST; 3s ago
     Docs: man:sshd(8)
           man:sshd_config(5)
  Process: 25768 ExecStart=/usr/sbin/sshd $OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 25769 (sshd)
   CGroup: /system.slice/sshd.service
           ├─20443 sshd: root@pts/1
           ├─20445 sshd: root@notty
           ├─20447 /usr/libexec/openssh/sftp-server
           ├─20594 -bash
           ├─23794 sshd: mysql [priv]
           ├─23796 sshd: mysql@pts/0
           ├─23797 sshd: mysql [priv]
           ├─23799 sshd: mysql@notty
           ├─23800 /usr/libexec/openssh/sftp-server
           ├─23991 -bash
           ├─25381 vim /etc/init.d/mysqld
           ├─25769 /usr/sbin/sshd
           └─25770 /bin/systemctl status sshd.service
 
4月 10 18:35:01 dap229-156 systemd[1]: Starting OpenSSH server daemon...
4月 10 18:35:01 dap229-156 systemd[1]: PID file /var/run/sshd.pid not readable (yet?) after start.
4月 10 18:35:01 dap229-156 sshd[25769]: Server listening on 0.0.0.0 port 22.
4月 10 18:35:01 dap229-156 sshd[25769]: Server listening on :: port 22.
4月 10 18:35:01 dap229-156 systemd[1]: Started OpenSSH server daemon.

At this time, there are no errors. The server can be logged in via SSH.

This problem is solved.

Recommended: linux system tutorial

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