NAT Inside Interface to OutSide Interface

Correct, 3cx is internal, I have 4 dell servers in my lab, I have 3cx running on debian internally.  I have to NAT that internal to external and open up port 5001, that way I can connect into their cloud service as well as hook it into Office 365 externally.  I would do a port translation on my edge router.

Basically I have a router, (internet provider), connected to a dude router, on the dude router I have my external interface for my firewall and one other device, this allows me to physically connect other devices in a dmz that I don't want to use the firewall for.  I just need to NAT it externally the cloud 3cx side to hook into it

Correct, 3cx is internal, I have 4 dell servers in my lab, I have 3cx running on debian internally.  I have to NAT that internal to external and open up port 5001, that way I can connect into their cloud service as well as hook it into Office 365 externally.  I would do a port translation on my edge router.

Basically I have a router, (internet provider), connected to a dude router, on the dude router I have my external interface for my firewall and one other device, this allows me to physically connect other devices in a dmz that I don't want to use the firewall for.  I just need to NAT it externally the cloud 3cx side to hook into it

Hi Stephen,

a better way to achieve what you are after is the following firewall rule.

LAN - > 3CX(IP address) -> WAN -> dude router (IP address) - > 5001 -> allow -> log.

You will not need a NAT between the 172 and the 192 address networks.

You will more than likely run into debugging issues with the VoIP because VoIP does not like double NAT which I assume you will have with your dud router and your ISP router?

Ian