80 lines
3.2 KiB
Nix
80 lines
3.2 KiB
Nix
{config, ...}: {
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# https://nixos.wiki/wiki/Networking
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# https://nixos.wiki/wiki/Systemd-networkd
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networking = {
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firewall = {
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# Allow some ports for ad-hoc use
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allowedTCPPorts = [1234 1337 8000 8080];
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allowedUDPPorts = [1234 1337 8000 8080];
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# Do not spam dmesg/journalctl with refused connections
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logRefusedConnections = false;
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};
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nameservers = ["159.69.4.2#dns.caspervk.net" "2a01:4f8:1c0c:70d1::1#dns.caspervk.net"];
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search = ["caspervk.net"];
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};
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# TODO: these systemd networkd settings will be the default once
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# https://github.com/NixOS/nixpkgs/pull/264967 is merged.
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networking.useNetworkd = true;
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systemd.network.enable = true;
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# The notion of "online" is a broken concept
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# https://github.com/nix-community/srvos/blob/main/nixos/common/networking.nix
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systemd.services.NetworkManager-wait-online.enable = false;
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systemd.network.wait-online.enable = false;
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# systemd-resolved provides DNS resolution to local applications through
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# D-Bus, NSS, and a local stub resolver on 127.0.0.53. It implements caching
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# and DNSSEC validation. We configure it to only, and always, use
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# dns.caspervk.net over TLS.
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# NOTE: It's surprisingly hard to get the system to always follow the custom
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# DNS servers rather than the DHCP-provided ones. Check the traffic with:
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# > sudo tcpdump -n --interface=any '(udp port 53) or (tcp port 853)'
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# or
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# > sudo resolvectl log-level debug
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# > sudo journalctl -fu systemd-resolved.service
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# https://nixos.wiki/wiki/Encrypted_DNS
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# https://nixos.wiki/wiki/Systemd-resolved
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services.resolved = {
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enable = true;
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dnsovertls = "true";
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# TODO: DNSSEC support in systemd-resolved is considered experimental and
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# incomplete. Upstream will validate for us anyway, and we trust it.
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# https://wiki.archlinux.org/title/systemd-resolved#DNSSEC
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dnssec = "false";
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# 'Domains' is used for two distinct purposes; first, any domains *not*
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# prefixed with '~' are used as search suffixes when resolving single-label
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# hostnames into FQDNs. The NixOS default is to set this to
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# `config.networking.search`, which we maintain. Second, domains prefixed
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# with '~' ("route-only domains") define a search path that preferably
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# directs DNS queries to this interface. The '~.' construct use the DNS
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# servers defined here preferably for the root (all) domain(s).
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# https://man.archlinux.org/man/resolved.conf.5
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domains = config.networking.search ++ ["~."];
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# Resolved falls back to DNS servers operated by American internet
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# surveillance and adtech companies by default. No thanks, I'd rather have
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# no DNS at all.
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fallbackDns = [];
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};
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# TCP BBR has significantly increased throughput and reduced latency. Note
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# that the IPv4 setting controls both IPv4 and IPv6.
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boot.kernel.sysctl = {
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"net.ipv4.tcp_congestion_control" = "bbr";
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};
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# vnStat keeps a log of hourly, daily and monthly network traffic
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services.vnstat.enable = true;
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environment.persistence."/nix/persist" = {
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directories = [
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{
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directory = "/var/lib/vnstat";
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user = "root";
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group = "root";
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mode = "0755";
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}
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];
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};
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}
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