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
8{
9 networking.firewall.enable = false;
10}
11```
12
13If the firewall is enabled, you can open specific TCP ports to the
14outside world:
15
16```nix
17{
18 networking.firewall.allowedTCPPorts = [ 80 443 ];
19}
20```
21
22Note that TCP port 22 (ssh) is opened automatically if the SSH daemon is
23enabled (`services.openssh.enable = true`). UDP ports can be opened through
24[](#opt-networking.firewall.allowedUDPPorts).
25
26To open ranges of TCP ports:
27
28```nix
29{
30 networking.firewall.allowedTCPPortRanges = [
31 { from = 4000; to = 4007; }
32 { from = 8000; to = 8010; }
33 ];
34}
35```
36
37Similarly, UDP port ranges can be opened through
38[](#opt-networking.firewall.allowedUDPPortRanges).