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The main content of this article is "how to check the version of SSH installed on the Linux system", interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn how to check the version of SSH installed on the Linux system.

Check the supported SSH protocol version

Method one

If you want to check the SSH version supported by your local OpenSSH server, you can refer to the / etc/ssh/sshd_config file. Open / etc/ssh/sshd_config with a text editor and view the "Protocol" field.

If shown below, it means that the server only supports SSH2.

The code is as follows:

Protocol 2

If shown below, it means that the server supports both SSH1 and SSH2.

The code is as follows:

Protocol 1,2

Method two

If you can't access / etc/ssh/sshd_config because the OpenSSH service is running on a remote server. You can use a SSH client called ssh to check the supported protocols. Specifically, it forces ssh to use a specific SSH protocol, and then we look at the response of the SSH server.

The following command forces ssh to use SSH1:

The code is as follows:

$ssh-1 user@remote_server

The following command forces ssh to use SSH2:

The code is as follows:

$ssh-2 user@remote_server

If the remote SSH server only supports SSH2, the first option with "- 1" will appear with an error message like the following:

The code is as follows:

Protocol major versions differ: 1 vs. 2

If the SSH server supports both SSH1 and SSH2, both commands are valid.

Method three

Another way to check the version is to run the SSH scanning tool, called scanssh. This command line tool is useful when you want to check a set of IP addresses or the entire local network to upgrade SSH1-compliant SSH servers.

Here is the basic SSH version scanning syntax.

The code is as follows:

$sudo scanssh-s ssh-n [ports] [IP addresses or CIDR prefix]

The "- n" option specifies the SSH port to scan. You can scan multiple ports with all-good separation. Without this option, scanssh will scan port 22 by default.

Use the following command to discover the SSH server in the 192.168.1.0 Compact 24 local network and check the v version of the SSH protocol:

The code is as follows:

$sudo scan-s ssh 192.168.1.0 take 24

If scanssh reports "SSH-1.XX-XXXX" for a specific IP address, this implies that the minimum version supported by the relevant SSH server is SSH1. If the remote server only supports SSH2,scanssh, "SSH-2.0-XXXX" will be displayed.

At this point, I believe you have a deeper understanding of "how to check the version of SSH installed on the Linux system". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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