The code I gave in my last reply with hard-coded values for IP addresses, works.

truptivk: what follows is intended not as a rebuke, but for future reference. When moritz asked for example code to run, the implicit assumption was that the code would demonstrate the problem, not that it would run just fine. I may not have been the only monk who spent time trying to figure out what (nothing) was wrong with the code. (Well, maybe just a little bit of a rebuke:)