Client trying to connect to a NATed Server IP

oandarilho01

Hi,

I have this unnusual setup: I have an OpenVPN server working pretty well.
All clients that I ever configured can connect instantly using the Public IP of the server in their "remote" line of the config files.

But the weird client is inside a big corporation which NATs any outside public IP to some of its internal IPs. And so, the "remote" line has to receive this internal IP and I think OpenVPN may be misleading by, perhaps, the headers of the arriving packets.

Am I clear?
The openvpn server has IP 2xx.xxx.xxx.xx and the client, instead of put this, is being forced to use

remote 172.xx.xxx.x

Need I something else than remote and port directives in client side, maybe something more on the server side...? The openvpn --help output didn't tell me much about NAT.

Any clues?

Thanks in advance

maikcat

I have this unnusual setup: I have an OpenVPN server working pretty well.

so its unusual to have an openvpn server working well? 😃

regarding the ip related questions,
if your internal ips located in range between 172.6-172.31 then there is NO way to
connect them from internet since these ips are private ip ranges...

NAT regarding openvpn is transparent and openvpn works with NAT...

Michael.

oandarilho01

maikcat wrote
I have this unnusual setup: I have an OpenVPN server working pretty well.
so its unusual to have an openvpn server working well? 😃

Hehe, my bad... 🙂

maikcat wroteif your internal ips located in range between 172.6-172.31 then there is NO way to
connect them from internet since these ips are private ip ranges...

NAT regarding openvpn is transparent and openvpn works with NAT...

Michael.

I'm afraid you didn't understand the scenario. The VPN server do have a valid public IP to receive the connection. And surely its VPNs are configured to have unique /30 private IPs (after connection). The weirdness is on the client side: the machines are forced to hit "special" internal IPs when they want, actually to access Internet resources.

E.g.: A machine wants to open 74.125.228.87:80 (one of google.com IPs), but instead of putting this in the browser, it HAS to put 172.16.0.100, which will be routed/natted to the real public Google's IP later, on the network "blackbox".

It's a bit clear now?
I do not understand why one network admin would want to do this, but I'm trying to gather information whether OpenVPN can or cannot handle this, to convince my customers' admins to help me.