diff options
Diffstat (limited to 'net.html')
| -rw-r--r-- | net.html | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/net.html b/net.html new file mode 100644 index 0000000..bc07c9b --- /dev/null +++ b/net.html @@ -0,0 +1,173 @@ +<!DOCTYPE html> +<html> + <head> + <title>Minimal Laptop Networking with NixOS</title> + <meta property="article:published_time" content="2026-07-29"> + <script src="article.js"></script> + </head> + <body> + <article> + <header></header> + + <p> + The default networking stack on NixOS uses NetworkManager. + While it's a great choice for many users, I prefer a lighter setup built around systemd-networkd, systemd-resolved, and iwd. It integrates well with the rest of the systemd stack, has fewer moving pieces, and exposes powerful networking features without an additional network management daemon. + </p> + + <p class="comment"> + This article focuses on laptops that connect to wifi. + If you're configuring a server, you probably don't need iwd at all; systemd-networkd and systemd-resolved are usually sufficient. + </p> + + <div id="toc"></div> + + <h2>The default stack</h2> + <p>If not configured otherwise, NixOS uses the following stack:</p> + <ul> + <li>NetworkManager for wifi</li> + <li>dhcpcd for DHCP</li> + <li>resolvconf for DNS</li> + <li>a "legacy script based system" for network configuration<sup><a href="https://search.nixos.org/options?channel=26.05&query=useNetworkd&type=options#show=option%253Anetworking.useNetworkd:~:text=legacy%20script%20based%20system">[1]</a></sup></li> + </ul> + <p>We'll be replacing it with:</p> + <ul> + <li>iwd for wifi</li> + <li>systemd-networkd for DHCP and network configuration</li> + <li>systemd-resolved for DNS</li> + </ul> + <p> + This has a few benefits. + Firstly, switching to resolved allows you to enable features like encrypted DNS over TLS (DoT) and DNSSEC validation, which reduces the potential for DNS spoofing and man-in-the-middle attacks<sup><a href="https://whynothugo.nl/journal/2026/06/24/ignore-dnssec-if-you-like-mitm-attacks/#distributions-and-oss">[2]</a></sup>. + Additionally, the default stack uses 3 extra packages (NM, dhcpcd, resolvconf) and some bash scripts, while this setup only uses one extra package (iwd). + Also, I'm kind of a systemd nerd, and this is a way to dig into systemd a bit more. + </p> + + <p>So the first thing we can do is disable all of the default stuff:</p> + <pre><code>{ + <prop>networking</prop> = { + <prop>networkmanager</prop>.<prop>enable</prop> = <kw>false</kw>; + <prop>dhcpcd</prop>.<prop>enable</prop> = <kw>false</kw>; + <prop>resolvconf</prop>.<prop>enable</prop> = <kw>false</kw>; + <prop>networking</prop>.<prop>useDHCP</prop> = <kw>false</kw>; + }; +}</code></pre> + + <p>And let's get to configuring!</p> + + <h2>iwd</h2> + <p> + First up is iwd. + The important parts of the configuration are delegating network configuration to networkd, delegating name resolution (DNS) to resolved, and configuring MAC randomization for some extra privacy. + </p> + <pre><code>{ + <prop>networking</prop>.<prop>wireless</prop>.<prop>iwd</prop> = { + <prop>enable</prop> = <kw>true</kw>; + <prop>settings</prop> = { + <prop>General</prop> = { + <prop>EnableNetworkConfiguration</prop> = <kw>false</kw>; <com># delegated to networkd</com> + <prop>AddressRandomization</prop> = <str>"once"</str>; + <prop>AddressRandomizationRange</prop> = <str>"full"</str>; + }; + <prop>Network</prop>.<prop>NameResolvingService</prop> = <str>"systemd"</str>; <com># use systemd-resolved</com> + }; + }; +}</code></pre> + + <p> + At this point, we don't have any network configuration yet, so internet access won't work. However, you can verify that iwd is functioning correctly: + </p> + <ul> + <li><code><kw>iwctl</kw> <prop>station</prop> <prop>wlan0</prop> <prop>scan</prop></code>: Scans for new wifi networks</li> + <li><code><kw>iwctl</kw> <prop>station</prop> <prop>wlan0</prop> <prop>get-networks</prop></code>: lists the networks that it found</li> + <li><code><kw>iwctl</kw> <prop>station</prop> <prop>wlan0</prop> <prop>connect</prop> <str>"<SSID>"</str></code>: connects to the network, prompting for a PSK if necessary</li> + </ul> + + <h2>systemd-networkd</h2> + <p> + Next up is systemd-networkd. + Networkd has lots of advanced options for things like static IP config, Wireguard tunnels, VLANs, domain-based DNS routing, and more. + However, here we'll just do a basic configuration to enable DHCP and deny DHCP-advertised DNS. + </p> + <details class="comment"> + <summary>why disable DHCP-advertised DNS?</summary> + By default, most networks advertise their own DNS resolver via DHCP. + Since we'll configure our own encrypted upstream DNS servers in the next section, we tell networkd to ignore the ones provided by the network. + </details> + + <pre><code>{ + <prop>systemd</prop>.<prop>network</prop> = { + <prop>enable</prop> = <kw>true</kw>; + + <prop>networks</prop>.<str>"11-default"</str> = { + <prop>name</prop> = <str>"wl*"</str>; + <prop>networkConfig</prop>.<prop>DHCP</prop> = <str>"yes"</str>; + + <com># never accept dhcp dns</com> + <prop>dhcpV4Config</prop>.<prop>UseDNS</prop> = <str>"no"</str>; + <prop>dhcpV6Config</prop>.<prop>UseDNS</prop> = <str>"no"</str>; + }; + }; + <prop>networking</prop>.<prop>useNetworkd</prop> = <kw>true</kw>; +}</code></pre> + + <p> + The <code>name = "wl*"</code> + refers to the network interface name that this configuration applies to. + According to the systemd docs, wireless LAN devices should start with the two-character prefix "wl"<sup><a href="https://www.freedesktop.org/software/systemd/man/latest/systemd.net-naming-scheme.html#:~:text=wl,WLAN">[3]</a></sup>. + Here we use a glob (<code>*</code>) to match all wireless interfaces. + </p> + + <p>You can verify that your configuration worked with a few commands:</p> + <ul> + <li><code><kw>ip</kw> <prop>addr</prop></code>: make sure that there's an IP address associated with your wireless interface. That means DHCP is working.</li> + <li><code><kw>networkctl</kw> <prop>status</prop></code>: make sure there's no significant errors in the logs.</li> + </ul> + + <h2>systemd-resolved</h2> + <p> + Now all we have left is DNS configuration, then we're done. + This is probably the part where you can nerd out the hardest, but I try to keep it pretty minimal. + The important parts are selecting upstream DNS servers that support secure DNS protocols (like DNS over TLS and DNSSEC) and that respect your privacy. + For these reasons, I use <a href="https://quad9.net">quad9</a>, but do your own research and find the best upstream DNS server for you! + Some other options include <a href="https://www.cloudflare.com/products/dns/">Cloudflare DNS</a>, <a href="https://developers.google.com/speed/public-dns/">Google's DNS</a>, or <a href="https://adguard-dns.io/en/public-dns.html">AdGuard Public DNS</a>. + </p> + <pre><code>{ + <prop>networking</prop>.<prop>nameservers</prop> = [ + <str>"9.9.9.9#dns.quad9.net"</str> + <str>"149.112.112.112#dns.quad9.net"</str> + ]; + + <prop>services</prop>.<prop>resolved</prop> = { + <prop>enable</prop> = <kw>true</kw>; + <prop>settings</prop>.<prop>Resolve</prop> = { + <prop>DNSOverTLS</prop> = <kw>true</kw>; + <prop>DNSSEC</prop> = <str>"allow-downgrade"</str>; + + <prop>LLMNR</prop> = <kw>false</kw>; + <prop>MulticastDNS</prop> = <kw>false</kw>; + }; + }; +}</code></pre> + + <p>You can verify your DNS configuration by using the <code><kw>resolvectl</kw> <prop>status</prop></code> + command or by just opening a website.</p> + + <h2>P.S. Captive portals</h2> + <p> + Captive portals are those wifi login pages that pop up when you connect to some public wifi networks. + Some captive portals don't behave correctly when you're using an encrypted third-party DNS server instead of the network's advertised resolver. + To get around this, I use <a href="https://github.com/FiloSottile/captive-browser">Captive Browser</a> + (<a href="https://search.nixos.org/packages?channel=26.05&query=captive-browser#show=captive-browser">nixpkgs</a>), which launches an instance of Chromium through a SOCKS5 proxy, avoiding the system DNS configuration altogether. + This allows you to access a captive portal for long enough to log in and gain internet access. + Pretty neat! + </p> + + <h2>P.P.S. I miss nm-applet</h2> + <p> + Probably the biggest downside to this setup is the lack of desktop integration. + GNOME and Plasma only support NetworkManager in their network configuration menu, so you're kinda out of luck. + For tiling window manager people, I can recommend <a href="https://github.com/e-tho/iwmenu">iwmenu</a>, which is a launcher (dmenu, rofi, fuzzel)-based menu for connecting to wifi networks via iwd. + </p> + </article> + </body> +</html> |