How to flush route table in windows?

I am trying to write a program that changes the default gateway of network time by time. But it seems that there are caches on the route table in every process so that I cannot control the network behavior accurately. Can I just flush route table to that process?

For example if I executed an Iexplore.exe first, then changed the default gateway to a Korean vpn, IE still went to amercia default gateway. But if I change the default gateway first and then execute Iexplore.exe, it went to Korea.

So how can I flush the route table cache? Thanks.


From command prompt as admin run:

netsh interface ip delete destinationcache

Works on Win7.