nix/host/x86_64-linux/home/Ovpn.nix

# easyrsa --days=36500 init-pki
# easyrsa --days=36500 build-ca
# easyrsa --days=36500 build-server-full <SERVER_NAME> nopass
# easyrsa --days=36500 build-client-full <CLIENT_NAME> nopass
# easyrsa gen-crl
# openssl dhparam -out dh2048.pem 2048
# Don't forget to set tls hostname on the client to match SERVER_NAME *AND* disable ipv6 ?

# easyrsa revoke <CLIENT_NAME>
# easyrsa gen-crl
# restart container

# SEE: https://github.com/OpenVPN/openvpn/blob/master/sample/sample-config-files/server.conf
# SRC: https://github.com/TinCanTech/easy-tls
{ pkgs, ... }:
{
  environment.systemPackages = with pkgs; [
    easyrsa
    openvpn
  ];

  users = {
    groups.openvpn = { };
    users.openvpn = {
      group = "openvpn";
      isSystemUser = true;
      # uid          = 1000;
    };
  };

  # NOTE: Change the `server` to match `cfg.clients` or write a substring here.
  services.openvpn.servers.vpn = {
    autoStart = true;
    config = ''
      ca /var/lib/ovpn/pki/ca.crt
      cert /var/lib/ovpn/pki/issued/home.crt
      client-to-client
      crl-verify /var/lib/ovpn/pki/crl.pem
      dev tun
      dh /var/lib/ovpn/dh2048.pem
      explicit-exit-notify 1
      group openvpn
      ifconfig-pool-persist ipp.txt
      keepalive 10 120
      key /var/lib/ovpn/pki/private/home.key
      persist-tun
      port 22145
      proto udp
      push "dhcp-option DNS 10.0.0.1"
      push "dhcp-option DNS 10.0.0.1"
      push "route 10.0.0.0 255.0.0.0"
      server 10.0.1.0 255.255.255.0
      status openvpn-status.log
      topology subnet
      user openvpn
      verb 4
    '';
  };
}