diff --git a/config/hosts/lifeline/configuration.nix b/config/hosts/lifeline/configuration.nix
index 1f53208..207e1ad 100644
--- a/config/hosts/lifeline/configuration.nix
+++ b/config/hosts/lifeline/configuration.nix
@@ -20,23 +20,23 @@
       interfaces.wg0 = {
         listenPort = 51820;
         ips = [
-          "172.16.50.1/24"
+          "172.18.50.1/24"
         ];
         peers = [
           {
             name = "mail-2";
             publicKey = "OIBOJlFzzM3P/u1ftVW2HWt8kA6NveB4PaBOIXhCYhM=";
             presharedKeyFile = "/secrets/wireguard-lifeline-mail-2-lifeline-psk.secret";
-            allowedIPs = [ "172.16.50.2/32" ];
+            allowedIPs = [ "172.18.50.2/32" ];
           }
         ];
         postSetup = ''
           ${pkgs.iptables}/bin/iptables -A FORWARD -i wg0 -j ACCEPT
-          ${pkgs.iptables}/bin/iptables -t nat -A POSTROUTING -s 172.16.50.0/24 -o ens6 -j MASQUERADE
+          ${pkgs.iptables}/bin/iptables -t nat -A POSTROUTING -s 172.18.50.0/24 -o ens6 -j MASQUERADE
         '';
         postShutdown = ''
           ${pkgs.iptables}/bin/iptables -D FORWARD -i wg0 -j ACCEPT
-          ${pkgs.iptables}/bin/iptables -t nat -D POSTROUTING -s 172.16.50.0/24 -o ens6 -j MASQUERADE
+          ${pkgs.iptables}/bin/iptables -t nat -D POSTROUTING -s 172.18.50.0/24 -o ens6 -j MASQUERADE
         '';
         privateKeyFile = "/secrets/wireguard-lifeline-wg0-privatekey.secret";
       };
@@ -46,7 +46,7 @@
       internalInterfaces = [ "wg0" ];
       externalInterface = "ens6";
       forwardPorts = [{
-          destination = "172.16.50.2:25";
+          destination = "172.18.50.2:25";
           proto = "tcp";
           sourcePort = 25;
       }];
diff --git a/config/hosts/mail-1/configuration.nix b/config/hosts/mail-1/configuration.nix
index c34643d..2418afc 100644
--- a/config/hosts/mail-1/configuration.nix
+++ b/config/hosts/mail-1/configuration.nix
@@ -44,11 +44,11 @@
       "wg0" = {
         matchConfig.Name = "wg0";
         address = [
-          "172.16.50.2/24"
+          "172.18.50.2/24"
         ];
         DHCP = "no";
         gateway = [
-          "172.16.50.1"
+          "172.18.50.1"
         ];
       };
     };
diff --git a/config/hosts/mail-1/simple-nixos-mailserver.nix b/config/hosts/mail-1/simple-nixos-mailserver.nix
index 63a0e3a..81fa130 100644
--- a/config/hosts/mail-1/simple-nixos-mailserver.nix
+++ b/config/hosts/mail-1/simple-nixos-mailserver.nix
@@ -59,11 +59,8 @@
 
   services.postfix = {
     transport = "relay:[mail-2.grzb.de]";
-<<<<<<< HEAD
     extraConfig = ''
       proxy_interfaces = 212.53.203.19
     '';
-=======
->>>>>>> 0e55e66 (Use systemd-networkd on mail servers)
   };
 }
diff --git a/config/hosts/mail-2/configuration.nix b/config/hosts/mail-2/configuration.nix
index 38384cb..1b622c7 100644
--- a/config/hosts/mail-2/configuration.nix
+++ b/config/hosts/mail-2/configuration.nix
@@ -44,11 +44,11 @@
       "wg0" = {
         matchConfig.Name = "wg0";
         address = [
-          "172.16.50.2/24"
+          "172.18.50.2/24"
         ];
         DHCP = "no";
         gateway = [
-          "172.16.50.1"
+          "172.18.50.1"
         ];
       };
     };
diff --git a/config/hosts/valkyrie/configuration.nix b/config/hosts/valkyrie/configuration.nix
index 008ead2..116e57d 100644
--- a/config/hosts/valkyrie/configuration.nix
+++ b/config/hosts/valkyrie/configuration.nix
@@ -48,23 +48,23 @@
         wg1 = {
           listenPort = 51822;
           ips = [
-            "172.16.50.1/24"
+            "172.18.50.1/24"
           ];
           peers = [
             {
               name = "mail-1";
               publicKey = "CyKPjkY1ah/lE6V3R0XugNo28doeAtD8wEtAeDB7bHs=";
               presharedKeyFile = "/secrets/wireguard-valkyrie-mail-1-valkyrie-psk.secret";
-              allowedIPs = [ "172.16.50.2/32" ];
+              allowedIPs = [ "172.18.50.2/32" ];
             }
           ];
           postSetup = ''
             ${pkgs.iptables}/bin/iptables -A FORWARD -i wg1 -j ACCEPT
-            ${pkgs.iptables}/bin/iptables -t nat -A POSTROUTING -s 172.16.50.0/24 -o ens3 -j MASQUERADE
+            ${pkgs.iptables}/bin/iptables -t nat -A POSTROUTING -s 172.18.50.0/24 -o ens3 -j MASQUERADE
           '';
           postShutdown = ''
             ${pkgs.iptables}/bin/iptables -D FORWARD -i wg1 -j ACCEPT
-            ${pkgs.iptables}/bin/iptables -t nat -D POSTROUTING -s 172.16.50.0/24 -o ens3 -j MASQUERADE
+            ${pkgs.iptables}/bin/iptables -t nat -D POSTROUTING -s 172.18.50.0/24 -o ens3 -j MASQUERADE
           '';
           privateKeyFile = "/secrets/wireguard-valkyrie-wg1-privatekey.secret";
         };
@@ -76,17 +76,17 @@
       externalInterface = "ens3";
       forwardPorts = [
         {
-          destination = "172.16.50.2:25";
+          destination = "172.18.50.2:25";
           proto = "tcp";
           sourcePort = 25;
         }
         {
-          destination = "172.16.50.2:465";
+          destination = "172.18.50.2:465";
           proto = "tcp";
           sourcePort = 465;
         }
         {
-          destination = "172.16.50.2:993";
+          destination = "172.18.50.2:993";
           proto = "tcp";
           sourcePort = 993;
         }