Selfhosted @lemmy.world Kokesh @lemmy.world 12 mo. ago

ISP put me behind NAT

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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Welcome to the world of Carrier Grade NAT. 100.64.0.0/10 is reserved for this.

If you are lucky, you also have an IPv6 address. The catch is you need IPv6 on the client-side too.

A VPS or similar running wireguard and a proxy might bridge the gap.

It might also be possible to ask your provider for some port forwarding. Probably not, but check anyway.

Good luck!

Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:

Fewer Letters	More Letters
CGNAT	Carrier-Grade NAT
DNS	Domain Name Service/System
Git	Popular version control system, primarily for code
HTTP	Hypertext Transfer Protocol, the Web
IP	Internet Protocol
NAT	Network Address Translation
VPN	Virtual Private Network
VPS	Virtual Private Server (opposed to shared hosting)
nginx	Popular HTTP server

[Thread #274 for this sub, first seen 11th Nov 2023, 18:30] [FAQ] [Full list] [Contact] [Source code]

You're already using cloudflare, so check out cloudflare tunnels. You install their software on your server which makes an outbound connection, bypassing the need for open ports or a public IP. Note this only does http traffic.

Another option is tail scale, which won't make your site public but will let you access it remotely on devices you have their software/app on.
A solid workaround is an ssh reverse tunnel with gateway ports enabled. You can do it for pennies with a cheap VPS.

With this option you open an ssh tunnel outbound and then you can connect back through it from the other side for whatever local services you want to run.

You first need a VPS with a public IP. Here's a guide that explains it: https://www.howtogeek.com/428413/what-is-reverse-ssh-tunneling-and-how-to-use-it/

Just remember to enable gateway ports in the VPS side sshd.conf and disable or adjust any firewall on the VPS so the internet can come in through the VPS ip address and tunnel back to your local system.
i've been on CGNAT and just pointed my domain to my ipv6 address with no issues - every isp should hand out huge v6 subnets dedicated to you.

Since my v6 prefix is not stable, i use ddclient from my homeserver to update my domains AAAA record
Have you reached out to your ISP to see if they can give you a dynamic public IP? I recently swapped to a new ISP that was using CGNAT but after contacting their support team with my use case, they were happy to set me up with a public IP so I could continue my self-hosting.
Buy a cheap VPS, setup a Wireguard or OpenVPN server (wg-easy is quite nice). Then something like Nginx Proxy Manager or plain nginx and expose your services over that.

Edit: if you need help, hit me up, love sharing my knowledge
You’re probably behind a CG-NAT. Look into establishing a tunnel, like via Cloudflare.
I use a VPN that I setup on an Oracle free tier VPS when I need to access my stuff over IPv4. I also have IPv6, so I can connect directly when using 5G on my phone.
Could always see if they offer a static IP. My ISP uses CG NAT and I just pay $10/month for a public static ip to bypass it.
Unless they're willing to give you your own IP (dynamic, or maybe static for a fee), that's a good reason for replacing your ISP imo.

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