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] 60 points 1 year ago (1 children)

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!

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

This is exactly what happened to me, but was able to contact my ISP to drop IPv6 support and get back my ports forwarding to work on my line

[–] [email protected] 24 points 1 year ago* (last edited 1 year ago)

N.B. to anyone reading this: ask your isp to "opt out of CG-NAT". Talking about IPv6 may confuse the staffer you're talking to, it's partially related but not the fully picture.

[–] [email protected] 51 points 1 year ago* (last edited 1 year ago) (4 children)

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]

[–] [email protected] 14 points 1 year ago
[–] [email protected] 7 points 1 year ago

Yo this bot is super helpful

[–] [email protected] 4 points 1 year ago

Oh I love this idea for a bot! Well done!

[–] vaselined 3 points 1 year ago
[–] [email protected] 35 points 1 year ago (1 children)

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.

[–] [email protected] 2 points 1 year ago (3 children)

I’m actually not sure you can easily get tailscale up and running om such as a setup as it uses the same cgnat ip range.

[–] [email protected] 9 points 1 year ago (1 children)

This page says (at the very bottom):

Tailscale can route its packets peer-to-peer over IPv4 or IPv6, with and without NAT, multi-layer NAT, or CGNAT in the path.

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

Yeah, you’re absolutely correct. I misread that thinking OP would have the CG NAT endpoint and taikscsle on the same physical device, which, I still think, would be a problem: you'd have two interfaces for 100.64.0.0/10. But if CG NAT terminates on the modem and you run taikscale on devices connected to it them there's surely no issue at all.

[–] c10l 2 points 1 year ago (1 children)

I run it on my router which has the CG-NAT IP address.

Whilst you’re right that it could clash, it’s very unlikely (a 1 in 4194302 chance), I imagine Tailscale would detect the clash and change IPs though I could be wrong as it never happened to me (and probably never will - though in all fairness it will eventually happen to someone).

[–] [email protected] 2 points 1 year ago

I went looking into how that works, and, apparently, tailscale adds individual node routes (in table 52). So yeah, you have very low chances of getting into trouble even if you have an interface with 100.64/10.

[–] c10l 6 points 1 year ago

Been using Tailscale behind CG-NAT for years. It works wonderfully and very rarely needs to route through the DERP infrastructure - it’s almost always a P2P connection.

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

I haven't had any issues running Tailscale and cloudflared on the same machines

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[–] nucleative 25 points 1 year ago (3 children)

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.

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

While I use ssh tunneling to access systems on a temporary basis, usually http, some caveats:

  • I don't know of a daemon to set up locally that will re-establish tunnels on power loss and the like. Not technically-difficult, but something one probably wants if this is going to be how he's gonna get at the system long-term rather than "I just need one-off access".

  • One other downside -- the service that the user here is aiming to expose is apparently ssh. For me -- reaching an http server -- wrapping the connection for remote use is desirable. For him, it probably isn't, as there'll be two layers of encryption. Not the end of the world, but it's a hit. You do want encryption in the outer protocol at least insofar as you need it to protect authentication to the VPS anyway.

[–] nucleative 2 points 1 year ago (3 children)

For reestablishing the connection, use the wrapper 'autossh'. It can be run from systemd so that it'll auto start and restart as you command it.

I have a couple instances using this that are absolutely rock solid after years.

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[–] kokesh 2 points 1 year ago (1 children)

I need more ports to be exposed - I'm running secure DNS, Git on one port, Webmin on other, Jelllyfin (I can live without that on data), HTTP server on 800/443, Homeassistant 8123,... I also had 3389 open for remote desktop to my Windows machine, etc.

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[–] [email protected] 24 points 1 year ago (10 children)

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

[–] [email protected] 16 points 1 year ago (1 children)

Unfortunately IPv6 adoption is not universal. There will be parts of the internet that won't be able to reach you at a 6-only address.

[–] [email protected] 2 points 1 year ago

Yup, my gemini capsule is suffering from it. :(

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[–] [email protected] 24 points 1 year ago (1 children)

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.

[–] nucleative 7 points 1 year ago (10 children)

This. I had the same situation being put behind CGnat and told them my security webcam needs port forwarding from outside and they had me back to a public IP within minutes.

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[–] plague_sapiens 20 points 1 year ago* (last edited 1 year ago) (2 children)

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

[–] [email protected] 11 points 1 year ago (2 children)

I second this. I use a couple of dirt cheap VPSs from racknerd ($24/yr for 1 CPU/512Mb ram, but you can find coupons online to get them for $10/yr 1CPU/768mb ram) one does port forwarding over wireguard to my mail server so I can keep all my data in house, the other hosts an NGINX reverse proxy for all my web services. Works great. I use the reverse proxy for nextcloud and jellyfin for myself and 6 other users. Never had an issue. (Well, never had an issue I didn't cause myself at any rate.)

It's a little harder to set up than some of the other suggestions, but it's cheap, fully transparent to users, and doesn't expose your home network to the outside world.

[–] [email protected] 9 points 1 year ago

(Well, never had an issue I didn't cause myself at any rate.)

As is tradition

[–] plague_sapiens 4 points 1 year ago

Netcup is my favourite hoster in the EU, but I live in DE. 2€/m for 2c, 2/4gb ram, lots of traffic. They have coupons from time to time or xmas/easter/... deals. The whole front- and backend works like a charm too. Upload your own isos/qcow images, download backups, KVM is awesomely implemented too. Sadly they don't take crypto and you need a call verification or id via mail for your first purchase (understandable as a german hoster), besides that just wonderful :)

[–] [email protected] 5 points 1 year ago* (last edited 1 year ago) (1 children)

Personally I would strongly recommend learning how to do all of this. And then abandoning it for tailscale or something similar once you know what they're doing behind the scenes. It's incredibly useful knowledge but it's also nice to have so much of the process automated and best practices like key rotation done for you. Plus unless your network is hugely crazy or enterprise, you can manage for the really great price of $0.

And if you really really want to self host (which I understand) there's headscale for a lot of the features.

[–] plague_sapiens 2 points 1 year ago

Thanks for the tip. Haven't used tailscale (or sth similar) yet. But I'll take a look into it :)

[–] SiblingNoah 9 points 1 year ago

You’re probably behind a CG-NAT. Look into establishing a tunnel, like via Cloudflare.

[–] [email protected] 8 points 1 year ago (3 children)

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.

[–] [email protected] 2 points 1 year ago (4 children)

Oracle is awesome in this one specific way. They suck in all other ways but this is really good.

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[–] DoomBot5 6 points 1 year ago (33 children)

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.

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

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.

[–] [email protected] 8 points 1 year ago (1 children)

You say that as if most don’t hold a monopoly in their available regions. At least in America, you typically have the choice of one, maybe more if you’re in a largeish city, and I suppose you have the option of a 5G hub but that’s terrible for running services.

[–] [email protected] 4 points 1 year ago* (last edited 1 year ago) (2 children)

Ouch, I was not aware of that. Here in scandinavialand we have a few local or regional ones in each area, plus a few big ones that cover the entire country.

Once the fiber is in the ground, "any" ISP can use them, regardless who buried it. I think it's a remnant from 20ish years ago when the default was ADSL over copper, and the telecom cables were considered public infrastructure.

[–] [email protected] 5 points 1 year ago

Dude I’d kill for that availability. Here, the companies own the infrastructure, and can offer to let others use it if they’d like but that doesn’t usually happen.

[–] Glitchington 3 points 1 year ago (2 children)

Yeah, the US is very limited in ISP options. In my area there is one massive provider, and two or three small providers. The massive provider does up to 1Gb but it's cable and speeds fluctuate. The other providers can manage 250Mb and that's it. Also, upload on ALL plans available in my area caps out at 20Mb/s. It's a joke and the city won't let any fiber companies in because of an exclusivity contract with the big cable provider. It's baaaaaad

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

I've had plenty of rants about Norwegian broadband (or lack thereof) over the past 25 years. It's a bit of a long story, but the gist of it is that during the 90's there was this one company (Telenor) which had practical monopoly on telecom (it was the private remnant of what used to be part of the government), and of course they didn't want to develop broadband 8nfrastructure as the made shitloads of money by selling ISDN at the time. Broadband was available in the biggest cities only, and even there it was limited. And the punchline of that joke was that when I was on dialup I had to pay by the minute. During that time, hearing about not having to pay by the minute in the US sounded like paradise to me.

But luckily competition happened, and Telenor realized they had to allow modernization or be left out of the market entirely. Small communities could sign up to have broadband "delivered", and once enough people had signed up for an ISP to considet it profitable, digging would start. Today, twenty years later, I'm pretty satisfied with how it turned out. I live practically in the middle of nowhere, in a tiny industrial town sqeezed to fit into the terrain, where three of the cardinal directions are blocked by mountains and the fourth being a fjord. And I have 1gbit both up and down.

[–] plague_sapiens 2 points 1 year ago

Exactly the same in many parts of DE. In Bavaria we have cable (docsis 3+) from Vodafone and then there's copper and fibre from Telekom (most other ISPs use their infrastructure). Depending on where you are in Germany, cables is provided by another company. There are some fibre companies too.

I'm currently moving from Nuremburg to a smaller town next to it. Currently I have 250/50Mbit/s and in the street I'm moving I can only utilize 100/40... Like wtf, 100m down the road there's the citiy hall, they have fibre and it's street to the next small city will get fibre next year. I won't until idk years. C'mon I would pay a shitton to get synchronous 1 Gbit/s. I'm gonna test 5G there too and maybe for my high bandwidth stuff that's an option. Still fucked up. It's 2023 an we still live in the stoneage of the internet. Fuck our politicians...

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