J) Remote Access to your Home Server

Accessing your home server from outside can be tricky. Please note that i am referring to accessing your home server from outside, not your home network. There is a big difference!

You want to access the services hosted on your home server.

Access to the home server means access to your home services. You can, and should, remap using the reverse proxy any service which is not on the home server itself.

Access to the home network means get an IP on the home network and behave like your device is plugged-in the home network. This is not desirable because it will expose the devices really on the internal network to additional risks: what if your mobile device, while outside, is compromised? You just opened an unsecured route to access home….

If you need access to the home network, and please think twice because 99% it is not what you really need, you should use wireguard instead of the following approach.

If you are sure that you need it, look into setting up a WireGuard tunnel on your opnSense, this is left as an exercise for you.

You have a network interface of some kind between your home and your ISP provider. It could be a router or a gateway, it can be provided by the ISP or a device you bought and connected. This device acts as a firewall of kind and ensures that your home network is not accessible from outside.

In other words, unless you do specific actions, your home network will not be accessible from outside. Let's see what you could try.

If your ISP assign you a real IP address, then you can try to forward one or more ports so that those are reachable from outside.

To achieve port forwarding, you need access to the network interface between your home and your ISP (your gateway, or modem, or router…) and the option must be available.

Anyway the hopes that this will work today are really slim, because:

• Often ISPs will forbid it
• Having a real IP today is really uncommon, CG-NAT is instead the new default.
• the really usefull ports like 80 (HTTP), 443 (HTTPS), 25 (email) are usually blocked by your ISP anyway

CG-NAT, or Carrier-Grade NAT, is today the de-facto standard for residential internet access. In other words, today having a public IP is basically impossible, unless you are a lucky American (where IP4 address pools where generously granted in the past to ISPs) or willing to pay a lot of money for a specific service. And even in this case, it might not be available.

If you are behind CG-NAT, port forwarding is moot and you have only two options left:

• Using a VPN service (not wireguard: a commercial VPN with exit nodes)
• Using an external server as bridge (using wireguard or SSH as tunnel)

In both cases, you need a server located externally to your home, and that can be reached from the internet, that you can use as an entry-point toward your home. The main difference is explained below.

There are providers out there called VPN providers, that will let your home network be hidden behind a fake exit point. You pay (and none will let you do this for free) and your home network connection toward the internet will be masked by the VPN exit node. Some of them will also let you do port forwarding (again, usually, for an extra price).

You will still have a dynamic IP address, and this solution also raise additional privacy concerns since now all your traffic goes trough a third provider which might not even be in your own country and obey different laws.

A VPN by itself, even with port-forwarding, is not yet enough, you still need a way to get back into the home server from outside.

Note: when talking about VPN, do not confuse this with Wireguard, which is still a VPN technically, but it's intended to work on the other direction, to get back inside.

Any server on the internet with an IP address can be used to access your home server. So why not rent one, even the cheapest VPS (Virtual Private Server), and make it your home access point away from home? The advantages over using a VPN are:

• Usually cheaper (VPS can be rented for a fraction of the cost of a VPN)
• More scalable: you can always upgrade when you want to a better / more expensive service
• Can also be used as off-site backup storage if you purchase enough storage
• You are in full control, you can even install your favorite OS yourself, given your VPS allows it.
• The IP is static and will never change (with VPN, the exit node usually changes over time)

Some possible disadvantage:

• One more server to install & manage beside the home server

Of course, if you have the means, go for a physical server which will guarantee you better privacy given that you will even rent the actual hardware. I do this, and it's about 20€ per month at the time of writing this page.

Once you have established how you can make your home server visible on the internet, let's see how you can make so that you can access your services too. As i wrote at the beginning, the focus is on making your home services accessible, not your home network. This, again, is for security and protection. I assume all your services are already protected behind reverse-proxy, even at home, that provides an HTTPS encrypted layer and a common SSO authentication (more on this here and here).

Unless you can have port-forwarding (but in this case you need to take care of Dynamic DNS), there are two ways to “get back in”. Both are encrypted:

• Using Wireguard: you setup a wireguard server at home, then you need to install and configure clients on all the devices connecting from outside
• Using an SSH tunnel providing port-forwarding: this will allow any device to access your services, and no specific setup on them.

A good approach is to leverage both technologies and setup both at the same time. Specially if you have two external servers and two ISPs, setting up both a WireGuard redirect as primary and an SSH tunnel as backup access would go a long way to ensure you cannot be locked out of your home server.

In this case, of course, the backup link will need to use a different port than the main one.

Is it secure? Yes, security is provided by the reverse-proxy + SSO, and privacy is guaranteed by using HTTPS on all services + encrypted SSH/Wireguard tunnels.

So, here are the assumption:

• You choose the “external server” solution
• You have two external servers: external and failback (optional)
• You have two ISPs at home (optional)

I have already stated elsewhere, but i will again state it here since it's very important. For this approach to be safe, you must:

• Use HTTPS on all your service. And i mean all.
• Use a reverse-proxy in front of all your services.
• Use strong authentication (proxy-auth, or Authelia or a similar services)

All these three points are covered by using NGINX reverse proxy + SSO as i describe in the linked pages.

I will try with some ASCII art to illustrate:

        ┌───────────┐         
        │Home       │         
        │ ▲ Server ▲│         
        └─┼────────┼┘         
          │        │          
          │        │          
          │        │          
   ┌──────┼─┐    ┌─┼──────┐   
   │ISP 1 │ │    │ │ISP 2 │   
   └──────┼─┘    └─┼──────┘   
          │        │          
          │        │          
          │        │          
┌─────────┴┐      ┌┴─────────┐
│External  │      │External  │
│ Server 1 │      │ Server 2 │
│          │      │          │
│┌────────┐│      │┌────────┐│
││ IPF n.1││      ││ IPF n.2││
│└────────┘│      │└────────┘│
└──────────┘      └──────────┘

The home-server will port-forward to external.mydomain.com via ISP 1 and, at the same time, to failsafe.mydomain.com via ISP 2.

If you have only one ISP or one external server, just ignore the other. Of course you can use any mix of two ISPs and one external server, or one ISP and two external servers as you like, each step is a bit less redundant than the other of course.

The IPF (IP forward) can be either one or a mix of the WireGuard or SSH tunnels described below.

Advantages of using WireGuard:

• Setup is much simpler than a stable SSH tunnel
• It's been created for this scope in mind
• It's fast anbd efficient

Using WireGuard tunneling has some drawbacks too:

• Your remote server must be able to install WireGuard

This page provides instructions on how to install and configure WireGuard on Gentoo.

This page provides you details on how to setup Wireguard redirects.

Advantages of SSH tunnels:

• Do not require any additional package on Linux (SSH is installed by default)
• Works in any settings, always, as far as SSH is available on both servers

Using SSH tunneling has some drawbacks too:

• SSH was not created for this scope, it's a stretch
• More complex to make the tunnel resillient to disconnections and network issues

OpenSSH is the default- SSH package installed in Gentoo.

This page provides you details on how to setup SSH Tunneling.