Before we cover external security and think of putting the Asterisk server onto our production network, we must consider the internal security of the system to ensure that it fits with our security policy and meets good security practice at least.
Internal host security can be achieved in a variety of ways and there are many applications and tools that we can use to aid us in this. We will not discuss all of the tools and add-ons we can use for generic system security. However, we will cover basic operating system hardening with Asterisk in mind, as well as the further steps we can take to ensure that the Asterisk system is running as securely as possible.
It is also important to consider the physical security of the Asterisk system. We may want to have it under lock and key along with our other important infrastructure devices.