I am looking to change from my ISP that provides a static public IP address to an ISP that only can provide a private IP address served by DHCP.

Router1 WAN: dynamic private IP from provider
VOIP server

Router2 (cloud instance) static public IP
Forwards all traffic to Router1 > VOIP server


How can I ensure Router2 will know how to route incoming traffic to Router1? Router1 will need to kepp telling Router2 where to send packets.

Thanks for your help.

If your new ISP provide only Private IP, probbly you are uable to do nothing for accept incoming connections
because you not control the (CG?)NAT of your new provider and ont hat way you are unable to open ports or services for incoming requests.

Thanks for your reply.

Could Router1 send Router2 a regularly scheduled Keep-Alive refreshing connection route info? All of Router2's outbound traffic only goes to Router1.

I do not understan what you ask, Sorry.

If all outbound go to router1 why you need to modify something on route2?
Simply let router1 to do the.. router...

Hi,

I need a static public IP address for the VOIP server to register with SIP providers.

I think the solution I need may be something like this:
https://mivilisnet.wordpress.com/2016/1 ... rough-nat/

I have not studied this to understanding yet.