How can I setup a VPN server behide a firewall with NAT?

[mdws2001]

Hello everyone.
I am going to setup a softether VPN server in Windows Server 2008R2 which is behind a firewall with a NAT to a true IP A.B.C.D. However, this server connect to internet is using an IP A.B.C.E. (All computers behind the firewall are using this IP to connect the internet.)

When I install the softether program in the computer, the program shows the ip is A.B.C.E but not A.B.C.D.
I tried to connect the softether VPN server with both the ip A.B.C.E and A.B.C.D, but also failed.

Then, how can I setup this VPN netnork?
Can anyone help me to solve this problem?
Thank you very much.

[moatazelmasry]

What is the device facing the internet? is it a router or a switch or so?`in this case maybe you can just add a nat forwarding rule that forwards the traffic to SoftEther?

[mdws2001]

moatazelmasry wrote:
> What is the device facing the internet? is it a router or a switch or
> so?`in this case maybe you can just add a nat forwarding rule that forwards
> the traffic to SoftEther?

Broadband to the firewall then to the switch to all the computers. (DHCP provided by the domain server.)
Actually, I have been set the NAT to A.B.C.D or A.B.C.E. However, both setting cannot connect the VPN Server from the client.

[cedar]

Please disable Kernel mode SecureNAT in virtual hub extended option.

Kernel mode SecureNAT acquires and uses an IP address got from DHCP server.
User mode SecureNAT is slow, but it uses the IP address which host OS have.