Darn, that picture was screwed. That here is the right one:
+-------------+   +-------linux--box-------+
| SDSL Router |   |                        |   +-----------------+
| 4 static IP |===1 <> firewall+bridge  <> 2===|     DMZ Hub    
|==>...
+-------------+   |                        |   +-----------------+
                  |           ^ ??         |
+-------------+   |                        |   +-----------------+
| ADSL Router |===3 <> firewall+routing <> 4===| Intranet switch
|==>...
|   dyn IP    |   |            ^           |   +-----------------+
+-------------+   +------------5-----------+
                               |
                     +------------------+
                     | WLAN Transceiver |
                     +------------------+
The routers were attached to the wrong interfaces/firewall chains.
Thanks again :-) >>>> Philipp
+--- --  -
 icq 63599319
 www.pealpjpain.net
          -  -- ---+