NOTE: Update HOSTS_ALLOW_NETWORK with the appropriate value for the local environment.
Solution
Create /etc/hosts.allow- # echo 'ALL- <net>/<mask>, <net>/<mask>, ' >/etc/hosts.allow where each <net>/<mask> combination (for example, '192.168.1.0/255.255.255.0') represents one network block in use by your organization that requires access to this system.