How to run sshd on port 500 in High Sierra?
To modify the ssh port, you have to edit the ssh launch daemon of the ssh server host:


disable SIP
open ssh.plist:

sudo nano /System/Library/LaunchDaemons/ssh.plist 

modify the &lt;key&gt;Sockets&lt;/key&gt; (example port here: 10022) from

    ...
    &lt;key&gt;Sockets&lt;/key&gt;
    &lt;dict&gt;
            &lt;key&gt;Listeners&lt;/key&gt;
            &lt;dict&gt;
                    &lt;key&gt;SockServiceName&lt;/key&gt;
                    &lt;string&gt;ssh&lt;/string&gt;
                    &lt;key&gt;Bonjour&lt;/key&gt;
                    &lt;array&gt;
                            &lt;string&gt;ssh&lt;/string&gt;
                            &lt;string&gt;sftp-ssh&lt;/string&gt;
                    &lt;/array&gt;
            &lt;/dict&gt;
    &lt;/dict&gt;
    ...


to

    ...
    &lt;key&gt;Sockets&lt;/key&gt;
    &lt;dict&gt;
            &lt;key&gt;Listeners&lt;/key&gt;
            &lt;dict&gt;
                    &lt;key&gt;SockServiceName&lt;/key&gt;
                    &lt;string&gt;10022&lt;/string&gt;
                    &lt;key&gt;Bonjour&lt;/key&gt;
                    &lt;array&gt;
                            &lt;string&gt;10022&lt;/string&gt;
                            &lt;string&gt;10022&lt;/string&gt;
                    &lt;/array&gt;
            &lt;/dict&gt;
    &lt;/dict&gt;
    ...

unload and load the daemon

sudo launchctl unload /System/Library/LaunchDaemons/ssh.plist 
sudo launchctl load /System/Library/LaunchDaemons/ssh.plist 

test the ssh daemon
enable SIP




An alternative, less intrusive approach is to create a second ssh launch daemon in /Library/LaunchDaemons/:


copy the ssh.plist

sudo cp /System/Library/LaunchDaemons/ssh.plist /Library/LaunchDaemons/ssh2.plist 

modify the ssh2.plist:

sudo nano /Library/LaunchDaemons/ssh2.plist 


change the key Label to

&lt;key&gt;Label&lt;/key&gt;
&lt;string&gt;com.openssh.sshd2&lt;/string&gt;


change the key &lt;key&gt;Sockets&lt;/key&gt; as described earlier
disable SSH in the System Preferences > Sharing > Remote Login
load the launch daemon:

sudo launchctl load -w /Library/LaunchDaemons/ssh2.plist 

with strict key checking enabled in the ssh config file on a ssh client host you may have to remove the ssh server from the known_hosts file of this remote host.
access the ssh server with ssh user@IP -p &lt;port&gt;