Let’s imagine we have an internal web app and we want to expose it securely over the internet only to a selected group of people. There are multiple ways to do it. One that is often used is to set up the virtual private network (VPN). In my home lab, I use VPN a lot. But with VPN it’s easy to expose too much. And what if I want to share an app just for development purposes with someone else. And also, I want the process to be as simple and straightforward as possible. It should be a solved problem in 2021, right? Well, it’s kind of is with Teleport. I use it a lot in my home lab because it saves me a lot of time and still keeps my containers/access organized and secure. Let’s go through concrete examples of exposing Jenkins and home router.
Assuming you have the Teleport already set up, you can add your apps in a similar way to described below:
1. In the teleport.yaml add:
- name: "jenkins"
- name: "router-olobok"
2. Setup wildcard SSL certificates (very first time only)
3. Go to “Applications” in your Teleport and you should be able to access 2 apps:
and also to “https://router-olobok.ssh.jarosik.online”
The “short version” is lacking details, so let’s add them here. You can find documentation about the Teleport here: https://goteleport.com/teleport/docs/ and the application section here: https://goteleport.com/teleport/docs/application-access/ It might seem like a lot, but most of these settings are very first time only. One detail that I initially missed is that for Jenkins I needed to add a rewrite for redirections to work correctly. Also, I keep teleport behind HAproxy which serves multiple domains already, so I needed to slightly modify the config to allow multiple subdomains just for the teleport.
acl teleport-acl ssl_fc_sni -i ssh.jarosik.online
acl teleport-apps-acl ssl_fc_sni -m end .ssh.jarosik.online
use_backend teleport-web-https-backend if teleport-acl
use_backend teleport-web-https-backend if teleport-apps-acl
Another interesting thing is that you can register an app from anywhere. This is an example of a web app running in a Virtualbox VM on my laptop and connected with a reverse tunnel to the teleport. All you have to do is this one line:
sudo teleport start --roles=app --token=$APP_TOKEN --auth-server=ssh.jarosik.online:443 --app-name="inout-app" --app-uri="http://localhost:8080"
For the above line to work, you have to have the teleport proxy exposed to the internet. But it’s a similar process if you want to expose an ad-hoc SSH node, e.g. your Rasperry Pi. And you only need to set up this teleport proxy once. After that, you can expose any app with just a single line. The “inout-app” will be exposed as “https://inout-app.ssh.jarosik.online” WITHOUT any additional configurations and with correct TLS/SSL certs (so a web browser won’t complain). And it will also appear in the teleport applications list like any other app. This “one-liner” kind of expose won’t work well because redirections will redirect to real sites. But it might be still useful in some cases. The config version works well, and I exposed many apps that I need (including a central logging system, routers UI, or PowerDNS). And because it’s over https, you can just open a web browser on your smartphone and have full access without any additional configuration!