After searching the abnormal information on the Internet, we know that the system needs to install SSH service.

1. Recurrence problem: SSH localhost

Connect to host localhost port 22: connection reused

2. Check if SSH: PS – ef|grep SSH is installed

If is not available, it needs to be installed.

3. Try to install: sudo apt get install openssh server

This is a solution found on the Internet, but an error is reported:

The prompt says: you need the following packages: openssh server, openssh client, openssh SFTP server, etc.

Note the required version number, 1:7.2p2 – 4ubuntu2.1 in the figure above

4. Install SSH bucket

Find the web address according to the version number https://launchpad.net/ubuntu/+source/openssh/1 :7.2p2-4ubuntu2.1

openssh_ The required package list is described in 7.2p2-4ubuntu2.1.dsc

Package-List:
 openssh-client deb net standard arch=any
 openssh-client-ssh1 deb net extra arch=any
 openssh-client-udeb udeb debian-installer optional arch=any
 openssh-server deb net optional arch=any
 openssh-server-udeb udeb debian-installer optional arch=any
 openssh-sftp-server deb net optional arch=any
 ssh deb net extra arch=all
 ssh-askpass-gnome deb gnome optional arch=any
 ssh-krb5 deb oldlibs extra arch=all

A little more… Actually, I have installed openssh client, openssh server, openssh SFTP server and SSH (in sequence), and all the packages are downloaded from this website.

5. Verification successful: SSH localhost