Information
The /etc/hosts.deny file specifies which IP addresses are not permitted to connect to the host. It is intended to be used in conjunction with the /etc/hosts.allow file. The /etc/hosts.deny file serves as a failsafe so that any host not specified in /etc/hosts.allow is denied access to the system.
Solution
Run the following command to create /etc/hosts.deny :
# echo "ALL: ALL" >> /etc/hosts.deny
Notes - Contents of the /etc/hosts.deny file may include additional options depending on your network configuration.