Exchange 2010 SP2 relay to internet

Hello everybody,

I have a question about enabling anonymous relay to the internet over MS Exchange 2010 SP2.

I did it like in this tutorial:http://www.youtube.com/watch?v=gj61RzL_WFc

It works OK with relaying from same subnet where is placed Exchange server.

But when I want to relay emails coming from different subnet I have to set IP address exactly. When I set IP range for that subnet it's not working.

I already have five subnets and it is same for all. IP range work just for subnet where is placed Exchange.

Would you please advise me where is the problem.

Thanks!