Answer by Kamil Maciorowski for How to match a subdomain name of a client and not just IP of that client with sshd server?

From man 5 sshd_config:

UseDNS

Specifies whether sshd(8) should look up the remote host name, and to check that the resolved host name for the remote IP address maps back to the very same IP address.

If this option is set to no (the default) then only addresses and not host names may be used in ~/.ssh/authorized_keysfrom and sshd_configMatch Host directives.

If this option is set to yes then host names may be used in sshd_configMatch Host directives. Specify

UseDNS yes

in sshd_config and then Match Host myclient.mydomain.net will work. Note you need to use Match Host for this, not Match Address.