I wish you would have given a little more information about what you are trying to do. If it is what I am imagining then I think "iproute" might be what you are looking for. I just read an article about it a couple of weeks back:
If it's throttling your web server then I believe the above should also work for that, or there is an apache module called "mod_bandwidth" if I recall correctly.
It's a gameserver so I guess I want to slow down TCP/IP across the board.
I want to simulate how it will perform on my DSL connection, but have it connected only to my LAN for testing purposes.