diff --git a/README.md b/README.md
index daf88cd..b8ba201 100644
--- a/README.md
+++ b/README.md
@@ -17,17 +17,10 @@ content of the config files:
 
 ```
 [NETWORK]
-# leftmost socket next to the console:
-enp1s0=wan     # the uplink, DHCP enabled, in netwoork n.x.y.z for  0 <= n < 192
-enp1s0=wan,192.168.1.0/24    # the uplink, DHCP enabled, may be in addition in local network 192.168.1.x
-                             # several networks might be specified, with comma separation
-                             # must not contain addresses defined on other interfaces!
-enp2s0=192.168.3.5     # the ip address of the device to be connected (DHCP or static),
-                       # range of last number: 1..254 (the address of the APU port will be 2 or 1)
-enp3s0=off             # disabled
-enp4s0=192.168.3.1/24  # our ip address, the static address of the connected device must
-                       # be within 1-254 and not match our own
-# rightmost socket, next to the usb plugs
+enp1s0=192.168.127.254   # leftmost socket: connect here a moxa with factory settings
+enp2s0=192.168.2.2       # connected device will get this ip via DHCP 
+enp3s0=192.168.3.3       #    or must be configured static to this IP
+enp4s0=dhcp              # rightmost socket is the uplink
 
 [ROUTER]
 3000=/dev/ttyUSB0       # routing 3000 to the internal serial port /dev/ttyUSB0
@@ -39,6 +32,45 @@ cfg=uniax   # the cfg file for the frappy server
 port=5000   # the port for the frappy server
 ```
 
+## network configuration
+
+The example above fits the most cases. Here a detailed description of possible settings:
+
+### fixed IP
+```
+enp2s0=192.168.3.5
+```
+Configure the IP address of the connected device to get the specified IP via DHCP or 
+configure the device to with this static IP. The last number must be within 1..254,
+the APU port itself will get 1 (or 2, if the specified IP is 1).
+
+### custom network
+```
+enp3s0=192.168.3.1/24  # our ip address, the static address of the connected device must
+                       # be within 1-254 and not match our own
+```
+24 means 24 bit = 3 bytes network address.
+A local network with static addresses. This way, the APU can get an other address than
+192.168.x.1 or 192.168.x.2 or the network address size might be defined other than 24.
+Probably needed rarely.
+
+### uplink via DHCP
+```
+enp4s0=wan    # or enp4s0=dhcp          
+```
+Uplink configured for DHCP in any network n.x.y.z with n < 192
+
+### customized uplink
+```
+enp1s0=wan,192.168.1.0/24
+```
+Add more networks to the allowed uplink range. More than one range is allowed, comma separated.
+Must not overlap networks specified for other ports!
+
+### disabled port
+```
+enp3s0=off             # disabled
+```