diff --git a/README.md b/README.md
index 0caecd0..e43318e 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,7 @@
   * [Deploy my-nginx-service](#deploy-my-nginx-service)
   * [Stick the nginx-ingress controler and my-nginx app together](#stick-nginx-ingress-and-tcp-service)
   * [Test exposed app on TCP-port 9000](#test-nginx-ingress-and-tcp-service)
+* [Running postfix in kubernetes](#running-postfix-in-kuberentes)
 
 ## Install k3s <a name="install-k3s"></a>
 https://k3s.io/:
@@ -89,7 +90,7 @@ spec:
 ```
 
 ## Enable client-IP transparency and expose TCP-port 9000 <a name="enable-client-ip-transp-expose-tcp-9000"></a>
-Enable client-IP transparency and expose my-nginx app on nginx-ingress TCP-port 9000: `kubectl edit service -n ingress-nginx ingress-nginx-controller`
+Enable client-IP transparency (X-Original-Forwarded-For) and expose my-nginx app on nginx-ingress TCP-port 9000: `kubectl edit service -n ingress-nginx ingress-nginx-controller`
 Find the `ports:`-section of the `ingress-nginx-controller` service and *ADD* the definition for port 9000:
 ```
 [...]
@@ -186,7 +187,7 @@ metadata:
   name: tcp-services
   namespace: ingress-nginx
 data:
-  9000: "default/my-nginx:80"
+  "9000": default/my-nginx:80::PROXY
 ```
 Apply with `kubectl apply -f tcp-services-config-map.yml`:
 ```
@@ -194,6 +195,8 @@ configmap/tcp-services created
 ```
 Subsequently the config-map can be edited with `kubectl edit configmap tcp-services -n ingress-nginx`
 
+**Changes to config-maps do not take effect on running pods! A re-scale to 0 and back can solve this problem: https://stackoverflow.com/questions/37317003/restart-pods-when-configmap-updates-in-kubernetes**
+
 ## Test exposed app on TCP-port 9000 <a name="test-nginx-ingress-and-tcp-service"></a>
 ```
 dominik@muggler:~$ curl -s http://10.62.94.246:9000
@@ -217,3 +220,10 @@ kubectl logs my-nginx-65c68bbcdf-xkhqj -f
 10.42.0.18 - - [23/Aug/2020:16:38:33 +0000] "PROXY TCP4 10.62.94.1 10.42.0.18 48558 9000" 400 157 "-" "-" "-"
 [...]
 ```
+
+# Running postfix in kubernetes <a> name="running-postfix-in-kuberentes"</a>
+https://www.tauceti.blog/post/run-postfix-in-kubernetes/
+
+Important in term of Deployment(one node)/Daemonset(all nodes)
+* hostNetwork: true
+* dnsPolicy: ClusterFirstWithHostNet
\ No newline at end of file