Hi!
I often read suggestions to use something like Tailscale to create a tunnel between a home server and a VPS because it is allegedly safer than opening a port for WireGuard (WG) or Nginx on my router and connecting to my home network that way.
However, if my VPS is compromised, wouldn’t the attacker still be able to access my local network? How does using an extra layer (the VPS) make it safer?
I often read suggestions to use something like Tailscale (…) safer than opening a port for WireGuard (WG)
I guess someone is trying really hard to upsell Tailscale there. But anyways it all comes down to how you configure things, Tailscale might come with more sensible defaults and/or help inexperienced user to get things working in a safe way. It also makes it easier to deal with the dynamic address at home, reconnects and whatnot.
Specifically about Wireguard, don’t be afraid to expose its port because if someone tries to connect and they don’t authenticate with the right key the server will silently drop the packets. An attacker won’t even know there’s something listening on that port / it will be invisible to typical IP scans / will ignore any piece of traffic that isn’t properly encrypted with your keys.
f my VPS is compromised, wouldn’t the attacker still be able to access my local network? How does using an extra layer (the VPS) make it safer?
The extra layer does a couple of things, the most important might be hiding your home network IP address because your domains will resolve the VPS public IP and then the VPS will tunnel the traffic to your network. Since your home IP isn’t public nobody can DDoS your home network directly nor track your approximate location from the IP. Most VPS providers have some security checks on incoming traffic, like DDoS detection, automatically rate limit requests from some geographies and other security measures that your ISP doesn’t care about.
Besides that, it depends on how you setup things.
You should NOT have a WG tunnel from the home network to the VPS with fully unrestricted access to everything. There should be firewall rules in place, at your home router / local server side, to restrict what the VPS can access. First configure the router / local VPN peer to drop all incoming traffic from the VPN interface, then add exceptions as needed. Imagine you’re hosting a website on the local machine 10.0.0.50, incoming traffic from the VPN interface should only be allowed to reach 10.0.0.50 port 80 and nothing else. This makes it all much more secure then just blunt access to your network and if the VPN gets compromised you’ll still be mostly protected.
You should NOT have a WG tunnel from the home network to the VPS with fully unrestricted access to everything.
This is what I came here to make sure was said. Use your firewall to severely restrict access from your public endpoint. Your wiregaurd tunnel is effectively a DMZ so firewall it off accordingly
I completely disagree with recommending exposing a port to someone who’s asking this very question about the relative risks.
If they lack the expertise to understand the risk differences, then they very much lack the expertise to securely expose a port.
How can you ever learn the risks of exposing ports if all answers are “if you don’t know you shouldn’t do it”?
The post explicitly recommends ONLY exposing the wireguard port, not 80/443/22 which one should usually not do anyways. Very different things!
Yes, and to be fair the OP doesn’t even need to expose a port on his home network. He can do the opposite and have the port exposed on the VPS and have the local router / server connect to the VPS endpoint instead. This will also remove the issues caused by having dynamic IPs at home as well.
And that’s a different animal (moving the goalposts, which is an excellent idea, but OP didn’t even think of doing this).
OP asked about exposing a local port, which is a Bad Idea 99.9% of the time, especially for someone asking why it’s a risk.
Using a VPS with reverse proxy is an excellent approach to adding a layer between the real resource and the public internet.
By learning before you take on the risk.
It’s not like this isn’t well documented.
If OP is asking this question, he’s nowhere near knowledgeable enough to take on this risk.
Hell, I’ve been Cisco certified as an instructor since 1998 and I wouldn’t expose a port. Fuck that.
I could open a port today, and within minutes I’ll be getting hammered with port scans.
I did this about 10 years ago as a demonstration, and was immediately getting thousands of scans per second, eventually causing performance issues on the consumer-grade router.
I self host because i do not trust companies. I will not even consider giving tailscale the keys to my kingdom.
The company Tailscale is a giant target and has a much higher risk in getting compromised than my VPN or even accessible services.
Understand the technology that you use and assess your use case and threat model.
The company Tailscale is a giant target and has a much higher risk in getting compromised than my VPN or even accessible services.
One must be careful about this mindset. A bunch of smart lightbulbs that are individually operated aren’t a particularly appealing target either. However, in aggregate… If someone can write a script that abuses security flaws in them or their default configuration … even though you’re not part of a big centralized target, you are part of a class that can be targeted automatically at scale.
Self hosting only yields better security when you are willing to take steps to adequately secure your self hosted services and implement a disaster recovery strategy.
To add to this, self-hosting is also best when you minimize everything - limited service, with limited functionality, on dedicated hardware that doesn’t share access to your internal network or storage. Folks who use point-and-click apps to install a half dozen unauthenticated docker containers, all open to the internet, running on the same PC they store the only copy of their family photos and music/movie collection on… make me crazy.
It’s very hard to compromise a VPN, they’re designed specifically to prevent that.
A random service being exposed to the entire Internet may not be secure, and could provide a way in to your network for someone.
The thing about something like TailScale or ZeroTier or Nebula is that it’s dynamic. These all behave similar to a multiplayer game … a use case every residential firewall should “just get.”
The ports that are “opened” can change regularly, they’re not some standard port that can just be checked to see if it’s open (typically).
Compare that to the average novice opening port 51822 for wireguard or 22 for SSH and you start to see the difference. With those ports, you’ve got a pretty good idea what’s on the other side and it might even be willing to talk to you and give you error messages or TCP ACK packets to confirm it’s there (e.g. SSH).
This advice is as you can probably imagine more relevant to things like OpenVPN that are notoriously hard to correctly configure or application protocols like SSH or HTTP.
With these mesh VPNs you also don’t have to worry about your home dynamic IP changing and breaking your connection at inopportune times… And that’s a huge benefit (IMO). It’s also very easy to tie in new devices to the network.
A lot of it is about outsourcing labor to programs that know how to set up a VPN and make management of it easy. That ties into security because … a LOT of security issues boil down to misconfiguration.
Wireguard doesn’t send anything back if the key is not correct.
Because of this, Tailscale port swapping is inconsequential vs wireguard here.
Tailscale transfers trust of your VPN subnet to a third party, which is a real security concern.
I agree SSH service will be attacked if they are plainly exposed, out of date and allow login challenges.
Also agree that under or misconfiguration is a massive cause for security issues.
Is it for security? I think is mostly recommended because your home router is likely to have a dynamic address.
This is in regards to opening a port for WG vs a tunnel to a VPS. Of course directly exposing nginx on your router is bad.
Quite often I see replies like “don’t open ports, use tailscale”. Maybe they mix different reasons and solutions, confusing people like me :D
The really nice thing about tailscale for accessing your hosted services is absolutely nothing can connect without authentication via a professionally hosted standard authentication, and there’s no public ports for script kiddies to scan for, spot and start hammering on. There’s thousands of bots that do nothing but scan the internet for hosted services and then try to compromise them, so not even showing up on those scans is a good thing.
For example, I have tailscale on my Minecraft server and connect to it via tailscale when away from home. If a buddy wants to join I just send a link sharing the machine to them and they can install tailscale and connect to it normally. If for some reason buddy needs to be cut off, I can just stop sharing to that account on Tailscale and they can no longer access the machine.
The biggest challenge of tailscale is also it’s biggest benefit. Nothing can connect without connecting through the tailscale client, so if my buddy can’t/won’t install tailscale they can’t join my Minecraft server
WG uses UDP, so as long as your firewall is configured correctly it should be impossible to scan the open port. Any packet hitting the open port that isn’t valid or doesn’t have a valid key is just dropped, same as any ports that are closed.
Most modern firewalls default to dropping packets, so you won’t be showing up in scans even with an open WG port.
Checking nmap’s documentation it looks like it’s perfectly possible to detect open udp ports
Wireguard is a VPN.
A VPN is preferable because what’s safer, making one hole, or making six holes? One, obviously.
