We have a VPS running CentOS 7.2.1511 on a public fixed IP address hosting an Asterisk server. We'd like to use it as an IPSec server so that another VPS behind a NAT (and dynamic IP) on CentOS 6.5 can connect to the Asterisk server inside the IPsec client.
The IPSec server should allow for multiple peers to connect (we'll have more Asterisk in the future) and you should create a private LAN for those peers (no need to assign a fixed IP in this private LAN for IPSec clients). Documentation should be provided on how to set up a new peer on the server.
Since this is for VoIP, minimal overhead should be used.
I am willing to pay higher rates for the most experienced freelancers