What is the primary role of /etc/hosts.allow?

The primary role of /etc/hosts.allow is to grant access to specific hosts. This file is part of the TCP Wrappers feature used in Linux systems, which provides a way to control access to services based on the host attempting to connect. By defining which hosts or networks are allowed to connect to certain services, system administrators can enhance security by limiting access to authorized users only.

In this context, /etc/hosts.allow lists the hosts or networks that are permitted to access specified services. When a connection attempt is made, the system checks the rules defined in this file to determine if the connection should be allowed. If a host is listed in /etc/hosts.allow for a given service, then that host is granted access, thereby fulfilling its primary function.

The other options pertain to different system functionalities. Configuring user permissions relates to file ownership and permission settings, while blocking all network access would typically involve firewall settings or other network configuration tools rather than this specific file. Managing system processes refers to process control which is unrelated to access control based on host identification.