Thanks, but i never used TELNET and Open-Wrt. I'm thinking about DD-WRT, as it has a GUI. Anyway: i disabled Hardware NAT and funny, my problem is gone! Now it seems almost ANY problem with this...

Region : Germany Model : TL-WDR3600 Hardware Version : V1 Firmware Version : 3.13.26 Build 130129 Rel.59449n ISP : Hi, all my systems are configured under "IP & MAC Binding". Binding is activated...