this post was submitted on 11 Nov 2023
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ISP put me behind NAT (self.selfhosted)
submitted 1 year ago* (last edited 1 year ago) by kokesh to c/selfhosted
 

I'm connected via a 4G modem. Got this setup about 3 years ago. In the beginning it was enough to look for the public IP (what's my IP). The modem showed some sort of private ip in the ui. I'm running stuff at home (Homeassistant, Gitea,) and bought a domain and pointed it to my home IP via Cloudflare. After some time I've noticed my modem shows the public IP also internally. For about 2 years now it ran flawlessly, the IP changed from time to time, but not really more than once in several weeks. For about a week all stopped working and the modem shows IP 100.xxxx and outside 85.something I guess I'm behind NAT now. Normal port forwarding on the modem is useless now. Is it possible to open the ports via UPNP? I've tried via miniupnp from my Ubuntu server, but it just throws an error.

upnpc -a ifconfig enp1s0| grep "inet addr" | cut -d : -f 2 | cut -d " " -f 1 22 22 TCP

Can I use this to somehow open the ports via UPNP on my modem and bypass the blocking? I can't even OpenVPN to my modem anymore.

EDIT: i also run AdguardHome, that I use as Private DNS on my Android phone

UPDATE: everything except Adguard Home used as Private DND on my Android works! I've used this: https://github.com/mochman/Bypass_CGNAT/wiki/Oracle-Cloud-(Automatic-Installer-Script) - free Oracle VPS + automated well described script. Even HTTPS works fine!

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[–] [email protected] 3 points 1 year ago* (last edited 1 year ago) (1 children)

Good luck getting a non CGNAT connection here without paying for it. Also it's not a breach of contract if it's not in the contract...

[–] [email protected] 4 points 1 year ago (1 children)

If they sell an "internet connection" then selling one behind a CGNAT is a breach of contract, because it is not a connection to the internet but only a selective forwarding service from within their intranet.

Similar to how the consumer protection agencies fought against fake speed promises and hidden "fair use" volume clauses, CGNAT should also be forbidden to be advertised as "internet".

[–] [email protected] 2 points 1 year ago* (last edited 1 year ago) (1 children)

We have more internet connections than IPv4's they can't just pull new ones out of their ass. Also IPv6 is internet too.

[–] [email protected] -2 points 1 year ago (1 children)

This is a myth. There are large swath of IPv4 address spaces totally unused and many ISPs hoard them without actually using them.

An IPv6 only internet connection would also still be miles better than CGNAT connection.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

How? You can literally turn IPv4 off on your whole network, or selectively by device. But if you turn off your IPv4 you will get cut off of a good chunk of the internet.

And the only reason we have unused IPv4's is because a big part of the internet is behind NAT of some kind like CGNAT.

[–] [email protected] 0 points 1 year ago (2 children)

There is nothing wrong with an organization sharing an single IPv4 internally via NAT, but if your ISP sells you a connection to the internet, this by definition means you get a unique public IP address, otherwise it isn't an internet connection.

IPv6 support could be better for sure, but it is still much better than not having an internet connection at all as in the case of a CGNAT.

[–] [email protected] 1 points 1 year ago (1 children)

CGNAT usually only applies to the IPv4. The IPv6 prefix you get is usually public.

[–] [email protected] 0 points 1 year ago (1 children)

"Usually"? In my experience usually this is not the case. Starlink for example promised to make ipv6 available like that, but AFAIK it is still CGNAT only.

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago) (1 children)

I can only talk how it is in Germany, where CGNAT with a public IPv6 prefix is the norm and a public IPv4 costs extra money unless you have a legacy contract.

[–] [email protected] 1 points 1 year ago (1 children)

In addition this also depends on the ISP.

[–] [email protected] 1 points 1 year ago (1 children)

I have experience with Vodafone, Deutsche Glasfaser and Unitymedia and they all did it like this. It also might depend on the state.

[–] [email protected] 1 points 1 year ago

Kinda expected that.
Vodafone usually does DS-Lite tunnel
Deutsche Glasfaser is a new player so CG-Nat was to be expected.

[–] DoomBot5 0 points 1 year ago (1 children)

No it doesn't. It means you have access to the internet through that company's infrastructure. You still have full access to the internet behind a CGNAT even if you can't be reached directly from the internet.

[–] [email protected] 0 points 1 year ago* (last edited 1 year ago) (1 children)

An internet connection by definition is two-way. The internet was designed as a network of interconnected computers. A one-way only connection like through a CGNAT is preventing you from doing a lot of things the internet was designed for.

[–] DoomBot5 0 points 1 year ago (1 children)

You have a 2 way connection as facilitated by the CGNAT gateway that routes responses back to your network.

[–] [email protected] 0 points 1 year ago (1 children)

If you have no unique public IP there are a lot of things you can't do, so it isn't a true two way connection.

[–] DoomBot5 0 points 1 year ago (1 children)

No, it just doesn't fit in your imagination, but it is a 2 way connection by definition. It's also everything the ISP promises when they give you an internet connection.

[–] [email protected] 1 points 1 year ago (1 children)

Sorry, but you are using a wrong definition of an internet connection. A internet connection has by definition a unique public IP, otherwise it is only a intranet connection. That has nothing to do with my imagination and I can assure you that I would never pay for a CGNAT connection as most of what I do with my internet connection is not possible with that crap.

[–] DoomBot5 0 points 1 year ago (1 children)

Your definition does not make it the definition. Nobody really cares about your definitions or what you would do with it. People care about the accepted definitions and what is the expectation.

[–] [email protected] 0 points 1 year ago (1 children)

That's like saying internet is not internet. And I very much expect my internet connection to have a public IP.

[–] DoomBot5 0 points 1 year ago (1 children)

No, I'm just saying you're wrong at this point. You just keep proving that to be true with every reply.

[–] [email protected] 0 points 1 year ago (1 children)

So I am wrong for saying water is water and not fire?

[–] DoomBot5 0 points 1 year ago (1 children)

Except you keep claiming it's fire. It's not fire, so stop calling it such.

[–] [email protected] 0 points 1 year ago (1 children)

You are extremly confused, sorry to say. Please look up the difference between "Internet" and "Intranet".

[–] DoomBot5 0 points 1 year ago (1 children)

No, I don't think I am. You're just wrong and don't want to admit it. Some self reflection will do you good.

[–] [email protected] 0 points 1 year ago (1 children)

There is nothing to admit. You are simply not willing to concede that the original definition of "internet" is still valid and watering that down serves no purpose other that muddling the waters and allowing huge corporations to increase their profits by cheating on their customers.

[–] DoomBot5 0 points 1 year ago (1 children)

See above comment for reply then sprinkle a bit of irony for the projection coming from you.

[–] [email protected] 0 points 1 year ago (1 children)

Well, if you insist on stanning for multi billion dollar companies that are cheating on their customers then I guess all we can do is to disagree.

[–] DoomBot5 0 points 1 year ago (1 children)

No, just disagreeing the bullshit of a clueless internet stranger.

[–] [email protected] 0 points 1 year ago (1 children)
[–] DoomBot5 0 points 1 year ago (1 children)

Yeah, but you really don't need to be an ass and flaunt it everywhere.

[–] [email protected] 0 points 1 year ago

You started with the impolite language...