Double NAT issue: from Hitron Chita to Nest Wifi Pro to Screens 4 / desktop Mac

[skafte]

Hi everyone 👋

Hope you are well.

I'm trying to access my desktop Mac remotely through the app 'Screens 4'. So far I've been unsuccessful and the app is saying that there's a problem with double NAT.

I've tried the methods outlined by the developers of Screens 4 (here), but with no luck.

Here's a breakdown of my setup:

• Router: Virgin Media Hitron Chita
• Static IP
• Connected to a Nest Wifi Pro
• Connected to a desktop Mac

I'm aware that the problem happens because I'm using the Nest Wifi Pro router as an extension of the Hitron Chita ISP router/modem, but I just can't work out how to solve the problem?!

Of the methods mentioned by Screens 4 (here), here are the results of my attempts:

1. Configure a PPPoE Connection Between the Router and Modem

I don't believe Virgin Media and/or the Hitron Chita router supports PPPoE.

2. Use the Router in Bridge Mode

This didn't seem to work. I enabled bridge mode as described here, but it didn't allow me to connect through Screens 4 even though it didn't produce the double-NAT error when in Bridge Mode.

3. Add the Router to the Modem's DMZ

Tried doing this, but it didn't seem to have an effect. I also believe it's not recommended to do this for security reasons(?).

4. Forward the Modem's Port 5900 (or 22) to the Router

Did not work either.

I should say that I have not had any success with making changes to the settings on the Nest Wifi Pro router and I'm not sure if I need to anyway; I believe that all the settings should be set on the ISP modem and not on the third-party router, right? That said, strangely, I cannot change the Nest Wifi Pro router to use a static IP even though I've got it 🤔

Has anyone in here got any experience with making this setup work? If so, I'd be eternally grateful for any help that you can offer!

Hope to hear from someone and many thanks in advance!

[skafte]

Yeah, that's what I thought! And we agree that this is where I should be able to see my actual IP address in the router settings, right?:

If so, then it's not the same as when I visit https://www.whatsmyip.org/ – where it's XX.XX-XX-XX.static.virginmediabusiness.co.uk (the X's obviously being numbers).

Feels like the static IP address given by Virgin is some kind of fake static IP! 😝

[legacy1]

Its possible on some routers the default is SNAT when setting up routing so this is a big error and you likely will never see incoming traffic so port forward will never work.

[skafte]

OK. Darn... Thanks for your help, but I give up 😕

[jem101]

What every single reply to your original query has managed to miss is the important point that you are on a VM business connection with a static IP address!

And how does this work? Well you are given a dynamic public WAN address which is what the Hub 'sees' and reports in the status - however the static address is done by a GRE tunnel back to a VM datacenter. All outbound traffic is routed down this tunnel

When you do a whatismyip.com lookup, it gives you the address of the tunnel endpoint, because that's what the 'internet' sees your traffic as coming from. Use this address for any remote access.

But the VM hubs are notoriously flakey for port forwarding, so even then you may well have issues. Personally, I'd abandon the static IP nonsense, put the hub into 'modem' or bridge mode (Residential Gateway RG mode, I think they call it on the Hitron), and use your own Nest as the router and do the port forwarding on that. Yes, you will technically be on a dynamic address, but they tend to be very sticky and can stay the same for months if not years.

[skafte]

Many thanks @jem101! -that was really helpful! I really appreciate your input on this!

So, before I call Virgin Media and ask them to revert to a dynamic IP; do you know if the bridge mode approach – of gaining remote access – will only work with a dynamic IP or is it all the same? If it's the same, then I might as well save myself from having to make the change.

Also, I have a Zebra printer connected to the wifi and it's installed on my computer using its IP address. I've experienced, before getting the static IP, that I would lose connection to it, and I've had to reinstall it. I haven't had the static IP for long enough to know, but I was hoping that a static IP would solve the problem as I thought that the dynamic IP switch was causing the problem. I should say that I am not very knowledgeable about this and so I am kind of just guessing my way... Do you think that the dynamic IP could have been causing this problem with the printer? If so, then I'm more likely to forget about the remote control in return for not having to re-install the printer all the time.

Hope you can help and many thanks!