Are there reliable tools that can simulate real life-like network conditions e.g. networks with different bandwidth, different latencies, packet loss etc...?
RakNet's FAQ has some recommendations for such tools:
How do I simulate lag?
In a hurry, use RakPeer::ApplyNetworkSimulator. But I recommend http://www.netlimiter.com/ instead. There is also Network Emulator Toolkit (NEWT) from http://blog.mrpol.nl/2010/01/14/network-emulator-toolkit/ or http://blogs.msdn.com/b/lkruger/archive/2009/06/08/introducing-true-network-emulation-in-visual-studio-2010.aspx
http://www.netlimiter.com isn't bad. The free version allows you to put different bandwidth limits on the connections in your machine. Not sure that it can do packet loss though.