Question about project 2 pfsense in site-to-site and nat

[farenheitcx]

Hi! I make a simple pfsense gateway with openVPN and works greats but now needed to make the things more complicated  ;D

• Have one pfsense on DC (Server-B) with a public IP but the ISP only allow to open 5 ports for security purpose, so this pfsense gateway will act as client on the site-to-site vpn. Only ports related to pfsense can be opened.

• The second pfsense is on other DC where we have full control on the WAN interface and ports. This will be my primary pfsense gw (Server-A).

Where I'm working arround. The possible solution!

• Access to port 25 with wan IP (public) of Server-A but redirect this traffic through the vpn on Server-B private openvpn ip.

Some questions

• This can make bottlenecks or significant delay on connections? Server-B and Server-A are on different locations in same country. Ping one to another have a good ping responses with 50ms.

• It's possible make nat to a not open port like ssh tunneling?

Thanks in advance!