WANem
Talvez, tente WANem , já o usei e achei extremamente útil para esses fins.
WANem is a Wide Area Network Emulator, meant to provide a real experience of a Wide Area Network/Internet, during application development / testing over a LAN environment.
WANem thus allows the application development team to setup a transparent application gateway which can be used to simulate WAN characteristics like Network delay, Packet loss, Packet corruption, Disconnections, Packet re-ordering, Jitter, etc.