Hacker News Reader

Comment by hamandcheese | Hacker News Reader

NixOS is great for a basic home router (I use it for my home router) but it’s networking config is still pretty rudimentary, and some things I would expect to work just don’t - i.e. port forwarding only works from outside your network, not inside.

I haven’t done much with vlans yet so I can’t comment on that.

View on HN

This has more to do with iptables/nftables I think. I solved this by adding my port forwarding rules to the prerouting chain and the output chain. You can use a jump to consolidate the rules, like so - https://gist.github.com/madjam002/d30f6000adf0761e92623f7de2...

As other commentators have said, switching to systemd networkd has allowed for more advanced network configurations than I ever managed with pfSense. IPv6 works pretty much out of the box with my ISP which uses DHCP prefix delegation, I can assign /64's to different VLAN networks, and more recently I set up network prefix translation (I think that's what it's called) for my lab kubernetes cluster so each pod gets a unique IPv6 address in the RFC 4193 range which maps to my actual ISP provided IPv6 prefix, so if I change ISP the IPs in the cluster would remain the same. Being able to expose Kubernetes services directly to the internet with unique IPv6 addresses is pretty nice :)

I would highly recommend to use systemd-networkd based networking which should be able to do almost everything if configured correct.

Is there a nix config wrapper for systemd-networkd?

NixOS still does everything I need it too, but the parent comment sounded like they had a bit more complex of a setup.

Not sure what you mean by config wrapper, but yes, systems-networkd is quite nice. Here's my home router setup with vlan1 for uplink to ISP, a bunch of other vlans for internal networks, and IPv6 prefix delegation to internal networks, and of course fireguard. All configured using systemd-networkd:

{ pkgs, lib, ... }:{

  networking = {
    useNetworkd = true;
    useDHCP = false;
    enableIPv6 = true;
  };

   networking.wireguard.interfaces = {
     wireguard = {
       ips = [ "172.20.60.1/24" ];
       listenPort = 61891;
       privateKeyFile = "/etc/nixos/secrets/wireguard-privateKey";
       peers = [
         {
           publicKey = "897mRPejuv9yVnmTvcUL7ckQkIiM0wnSgHmgR15Evyw=";
           allowedIPs = [ "172.20.60.10/32" ];
           presharedKeyFile = "/etc/nixos/secrets/wireguard-presharedkey";
         }

...

  systemd.network.networks = {
    "10-eno1" = {
      matchConfig.Name = "eno1";
      networkConfig.LinkLocalAddressing = "no";
      networkConfig.DHCP = "no";
      extraConfig = ''
        VLAN=wan
        VLAN=vlan99
        VLAN=vlan30
        VLAN=vlan20
        VLAN=vlan1
        VLAN=podnet
        LLDP=no
        EmitLLDP=no
        IPv6AcceptRA=no
        IPv6SendRA=no
      '';
    };
    "11-vlan1" = {
      matchConfig.Name = "vlan1";
      linkConfig.RequiredForOnline = false;
      networkConfig.DHCP = "no";
      networkConfig.Address = "192.168.1.1/24";
      networkConfig.Domains = "tanso.net";
      networkConfig.ConfigureWithoutCarrier = "yes";
    };
    "11-podnet" = {
      matchConfig.Name = "podnet";
      linkConfig.RequiredForOnline = false;
      networkConfig.DHCP = "no";
      networkConfig.Address = "172.20.2.1/24";
      networkConfig.Domains = "tanso.net";
      networkConfig.ConfigureWithoutCarrier = "yes";
    };
    "11-vlan20" = {
      matchConfig.Name = "vlan20";
      networkConfig.DHCP = "no";
      networkConfig.Address = "172.20.20.1/24";
      networkConfig.Domains = "tanso.net";
      networkConfig.ConfigureWithoutCarrier = "yes";
      extraConfig = ''
      IPv6SendRA=yes
      DHCPv6PrefixDelegation=yes
      '';
    };

....

  systemd.network.netdevs = {
    "11-vlan1" = {
      netdevConfig = { Name = "vlan1"; Kind = "vlan"; };
      vlanConfig.Id = 1;
    };
    "11-podnet" = {
      netdevConfig = { Name = "podnet"; Kind = "vlan"; };
      vlanConfig.Id = 2;
    };
    "11-vlan20" = {
      netdevConfig = { Name = "vlan20"; Kind = "vlan"; };
      vlanConfig.Id = 20;
    };
    "11-vlan30" = {
      netdevConfig = { Name = "vlan30"; Kind = "vlan"; };
      vlanConfig.Id = 30;
    };

> Is there a nix config wrapper for systemd-networkd?

The options under systemd.network almost map 1:1 to systemd-networkd ones.

Port forwarding not working from inside the gateway sounds like it’s not doing hairpin NAT by default. I’m running a NixOS home router pair, not currently doing any port forwarding but now I’ll have to check that tonight, if nothing else people might appreciate an option for it.

Reply on news.ycombinator.com