pyrox.dev
1# Firewall {#sec-firewall}
2
3NixOS has a simple stateful firewall that blocks incoming connections
4and other unexpected packets. The firewall applies to both IPv4 and IPv6
5traffic. It is enabled by default. It can be disabled as follows:
6
7```nix
8networking.firewall.enable = false;
9```
10
11If the firewall is enabled, you can open specific TCP ports to the
12outside world:
13
14```nix
15networking.firewall.allowedTCPPorts = [ 80 443 ];
16```
17
18Note that TCP port 22 (ssh) is opened automatically if the SSH daemon is
19enabled (`services.openssh.enable = true`). UDP ports can be opened through
20[](#opt-networking.firewall.allowedUDPPorts).
21
22To open ranges of TCP ports:
23
24```nix
25networking.firewall.allowedTCPPortRanges = [
26 { from = 4000; to = 4007; }
27 { from = 8000; to = 8010; }
28];
29```
30
31Similarly, UDP port ranges can be opened through
32[](#opt-networking.firewall.allowedUDPPortRanges).