OVPN server setup problem

[cliver]

I'm trying to setup an OVPN server on my RT-AX88U on Rmerlin FW 3004.388.8_2.
I am connected to the WAN via a fibre modem (Voneus UK) which I have no access to.
The allocated WAN IP address is 100.xxx.xxx.xxx
The VPN Server setup page tells me

The wireless router currently uses a private WAN IP address (192.168.x.x, 10.x.x.x or 172.16.x.x). Please refer to the FAQ and set up the port forwarding

It's not in the ranges 192.168. 10. or 172.16. so, is this correct?
If so, is there any way around this as I don't have access to the fibre modem?
Or, will I have to use a different VPN server as the others don't seem to have this limitation?
If so which would be the better option?

 

[ColinTaylor]

The allocated WAN IP address is 100.xxx.xxx.xxx

This is a CGNAT address, which is a form of private address. It is not accessible from the internet therefore your OpenVPN server will be unreachable.

 

[cliver]

This is a CGNAT address, which is a form of private address. It is not accessible from the internet therefore your OpenVPN server will be unreachable.

Thanks for the swift reply. So, I take it from that the alternatives like IPSec or Wireguard won't work either?

 

[ColinTaylor]

So, I take it from that the alternatives like IPSec or Wireguard won't work either?

Not as far as I know.

People tend to use something like Tailscale or ZeroTier to get around CGNAT problems.

Installing Tailscale through Entware

Third party firmware for Asus routers (newer codebase) - RMerl/asuswrt-merlin.ng

github.com

 

[cliver]

Looks like I may have to cough up for a static ip.

 

[lgkahn]

IF you have another location that is not cgnat you can setup a full time openvpn tunnel to that location and from any machine on that network your network behind cgnat will be reachable..

i do that with one asus router on my starlink cgnat network to another on spectrum in a separate location..

 

[eibgrad]

Looks like I may have to cough up for a static ip.

I'm curious what that might cost. My ISP requires a business account upgrade, which is a significant cost (starts @ $200/month w/ 12 month commitment). For a $6 a month, you can create your own cloud-based OpenVPN Access Server w/ Digital Ocean.

 

[cliver]

I'm curious what that might cost. My ISP requires a business account upgrade, which is a significant cost (starts @ $200/month w/ 12 month commitment). For a $6 a month, you can create your own cloud-based OpenVPN Access Server w/ Digital Ocean.

I've just ordered a static IP with my ISP (Voneus) it's £5/month. Did a bit of research and some provide static IP's for free others up to around £5 per month. I'll look around again when my contract is due for renewal.