How can i simulate network problems between unix machines ?

Hello all
i need to simulate method invocations between 2 machine ( using corba )
now i like to test the method invoke timeout from machine1 to machine2 for that i need to
simulate network being busy , can it be done some how ?

If network is busy, packet buffers will be full and routers will start dropping packets. So, you may probably test by dropping outgoing packets matching a certain src/dest IP/port with a firewall, such as iptables on Linux.

By the way, I just browse the Linux kernel configuration and it has a packet generator for network stress testing!

hello and Thanks for the fast reply
but i am abegginer in networking and i need to follow
some kind of step by step tutorial
do you know about somekind of tutorial ?
By the way im using sunos 9 not linux
Thanks alot