Setup mail server and restructure some things

config/hosts/mail-1/configuration.nix

@@ -0,0 +1,61 @@
+{ ... }:
+{
+  boot.loader.grub = {
+    enable = true;
+    device = "/dev/vda";
+  };
+
+  networking = {
+    hostName = "mail-1";
+    useDHCP = true;
+    defaultGateway = {
+      address = "172.16.50.1";
+      interface = "wg0";
+    };
+    interfaces.enp6s18.ipv4 = {
+      routes = [
+        {
+          address = "10.201.0.0";
+          prefixLength = 16;
+          via = "10.202.41.1";
+        }
+        {
+          address = "10.202.0.0";
+          prefixLength = 16;
+          via = "10.202.41.1";
+        }
+        {
+          address = "172.21.87.0"; # management VPN
+          prefixLength = 24;
+          via = "10.202.41.1";
+        }
+        {
+          address = "217.160.117.160"; # 
+          prefixLength = 32;
+          via = "10.202.41.1";
+        }
+      ];
+    };
+    wireguard = {
+      enable = true;
+      interfaces.wg0 = {
+        ips = [
+          "172.16.50.2/24"
+        ];
+        peers = [
+          {
+            name = "lifeline";
+            publicKey = "g3xZ5oJCbPtzYDPTVAS400FDw6kirGR+7300bwiZDUY=";
+            presharedKeyFile = "/secrets/wireguard-lifeline-mail-1-mail-1-psk.secret";
+            endpoint = "lifeline.io.grzb.de:51820";
+            allowedIPs = [ "0.0.0.0/0" ];
+            persistentKeepalive = 25;
+          }
+        ];
+        privateKeyFile = "/secrets/wireguard-lifeline-mail-1-mail-1-privatekey.secret";
+      };
+    };
+  };
+
+  system.stateVersion = "23.05";
+}