{
  roles.default.perInstance = { ... }: {
    nixosModule =
      {
        lib,
        ...
      }:
      {

        systemd.network.networks."45-ppp0" = {
          matchConfig.Name = "ppp0";
          networkConfig = {
            DHCP = "ipv6";
            # pppd owns the v4 address/route on this link; don't let networkd
            # tear them down.
            KeepConfiguration = "static";
            # Default v6 route comes from the ISP's RA when they send one.
            IPv6AcceptRA = true;
          };
          # Many PPPoE ISPs never send an RA with the M flag; solicit regardless.
          dhcpV6Config.WithoutRA = "solicit";
          linkConfig.RequiredForOnline = "no";
        };

        boot.kernel.sysctl."net.ipv6.conf.all.forwarding" = lib.mkDefault 1;

      };
  };
}