FreePBX distro, altering iptables and adding dhcpd

I run small office which uses an older centos box that has asterisk installed. I painstakingly configured asterisk with the configuration files. Unfortunately, because the way our provider handles the internet handoff, I had to make the asterisk box the nat device for the office.

I would like to implement freepbx for a new iteration of the server, so I have decided to just deploy the FreePBX solution you folks provide

Upon installation, I noticed that it has an elaborate set of chains that are used.

Is it frowned upon to alter the iptables rules?

Additionaly, what about dhcpd? Can I configure it on the same box? Does FreePBX support provisioning of phones (Polycom 320)?

Thank you for your time.

Sure you can install DHCPD with yum

The chains are for the fail2ban ids. You certainly can add your own chains.

I would much rather see you use an external stateful firewall and forward the ports.

Take a look at the end point manager in the store for the tool to provision your Polycoms

Thank you for your response. I had to combine my nat device with my asterisk box in the past, I believe because I was unable to properly use the asterisk box behind the nat device, thus they had to be combined.

Does the end point manager require a license?