---
title: "Requirements"
description: "What a slopscale server needs: a public address, HTTPS on port 443, the ports the DERP relay and metrics use, and the paths these docs assume."
sidebar:
  label: "Requirements and Assumptions"
---

Slopscale should just work as long as the following requirements are met:

- A server with a public IP address for slopscale. A dual-stack setup with a public IPv4 and a public IPv6 address is
  recommended.
- Slopscale is served via HTTPS on port 443[^1] and [may use additional ports](#ports-in-use).
- A reasonably modern Linux or BSD based operating system. Release binaries and container images cover Linux
  (amd64, arm64, armv7); macOS and FreeBSD are [built from source](/slopscale/setup/install/source).
- A dedicated local user account to run slopscale.
- A little bit of command line knowledge to configure and operate slopscale.

## Ports in use

The ports in use vary with the intended scenario and enabled features. Some of the listed ports may be changed via the
[configuration file](/slopscale/ref/configuration) but we recommend to stick with the default values.

- tcp/80
    - Expose publicly: yes
    - HTTP, used by Let's Encrypt to verify ownership via the HTTP-01 challenge.
    - Only required if the built-in Let's Encrypt client with the HTTP-01 challenge is used. See [TLS](/slopscale/ref/tls) for
      details.
- tcp/443
    - Expose publicly: yes
    - HTTPS, required to make Slopscale available to Tailscale clients[^1]
    - Required for the [embedded DERP server](/slopscale/ref/derp), which is on by default
- udp/3478
    - Expose publicly: yes
    - STUN, required for the [embedded DERP server](/slopscale/ref/derp), which is on by default
- tcp/9090
    - Expose publicly: no
    - [Metrics and debug endpoint](/slopscale/ref/debug#metrics-and-debug-endpoint)

## Assumptions

The slopscale documentation and the provided examples are written with a few assumptions in mind:

- Slopscale is running as system service via a dedicated local user `slopscale`.
- The [configuration](/slopscale/ref/configuration) is loaded from `/etc/slopscale/config.yaml`.
- SQLite is used as database.
- The data directory for slopscale (used for private keys, policy, SQLite database, …) is located in `/var/lib/slopscale`.
- URLs and values that need to be replaced by the user are either denoted as `<VALUE_TO_CHANGE>` or use placeholder
  values such as `slopscale.example.com`.

Please adjust to your local environment accordingly.

[^1]: /slopscale/setup/The Tailscale client assumes HTTPS on port 443 in certain situations. Serving slopscale either via HTTP or via
    HTTPS on a port other than 443 is possible but sticking with HTTPS on port 443 is strongly recommended for
    production setups. See [issue 2164](https://github.com/juanfont/headscale/issues/2164) for more information.