Allow access
vi /etc/hosts.allow
add (you can add multiple lines, which ": allow" can save rate)
sshd: 192.168.81 *:. # Represents the allow 192.168.81 * ip ssh segment can access.
Sshd: All : allow # representation allow ssh access to all the ip
sshd: 192.168.81.74: allow # representation allow access 192.168.81.74ssh
Access Denied
vi /etc/hosts.deny
add (you can add multiple lines, which ": deny" can save rate)
sshd: All: deny # refused access to all ip
sshd: 210.13.218 *:. Deny # refused 210.13. 218. * ip ssh access to all segments
sshd: 192.168.81.74 # refused 192.168.81.74 host ssh access
After editing save the file, restart the service to be effective, execute reboot command
service xinetd restart
When hosts.allow and hosts.deny configuration conflicts, to hosts.allow prevail.