Basically i need to know how to clear the forward and reverse dns lookups and the dhcp list on our windows sbs 2011. we are having extreme network bandwidth issues. upstream of the server the speed is great, right on par with where we are paying for (50mbps with ping of 24ms )but immediately downstream of the server though it drops to about 1mbps with a ping of 1024ms. the network equipment is setup properly, they are managed switches with no bandwidth limits anywhere on the network. i have restarted the server to no change. the server is the DC and dhcp server. the only thing i can think of at this point to is to clear all the leases in the scope that aren't reserved and the dns lookups and caches. I'm just not sure how to do all this and what effects it will have on the clients on the network.