Zyxel Keenetic 4g + L2TP + No-IP + Ubuntu: how can I make all this friends?

Question

linux

I have a server with ubuntu, a router and a domain on no-ip. The provider gives a dynamically external IP address through the L2TP tunnel. The firmware of the router of the second branch, I really don’t want to sew up the first one.
You need to make sure that everything that is sent to the domain comes to the server that connects through the router. And to go back as expected. And ideally, so that the server receives from the DHCP router the IP that the provider has allocated for L2TP.
I can't think of a way to screw this up. Save help please.

Answer 1

Make static NAT translation of the necessary ports to the server ... What is the question? The router seems to support no-ip.
No, it is impossible to give the server the IP address of the external interface of the router (and if it is possible, it is still impossible).

Answer 2

Raise inadyn on the server and push it to the DMZ - something like that, isn't it? :)

Answer 3

1. We reserve the IP address for the server in the router's DHCP.
2. We configure PAT on the router (at least for all ports, if desired. I just can’t understand why the server needs all the traffic when certain ports are usually enough?) from the L2TP interface to the server’s internal IP address.
3. We bind the domain on no-ip to the router, there is a built-in client there.
4. ???
5. PROFIT!!!
Everything looks, to be honest, nowhere is easier, but something tells me that there are some pitfalls that you have encountered? If so, I would like to hear specifics.

Answer 4

I’ll describe the router setup step by step in a little more detail.
1. We bind the No-IP domain to the router (it is assumed that it is registered, judging by the topic):
Web muzzle - Broadband - DyDNS - No-IP service - fill in the fields "Domain", "Login" and "Password", check the box on the looking Internet interface (L2TP0).
2. Go to Home - Static DHCP Bindings - add - register the name of the server with ubuntu, its poppy and the desired ip.
3. Set up NAT on the router by telnetting to it:

(config)> ip nat %LANname%

//interface name that looks into the local network. by default Home.

(config)> ip static tcp L2TP0 80 server_ip 80

//ip static adds translation, tcp - transport, L2TP0 - interface looking to the outside world, 80 - port number to be translated, server_ip - server address to which we are broadcasting, 80 - port number _to_ to be translated. Repeat for each desired port. It is also possible from the web muzzle through Security - Address Translation Rules, but through the CLI it is faster, IMHO.
Here, like, that's all. Just in case and for the future: manual for CLI firmware v.2.00.