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So far we've talked about some of the issues you might come across when working with DHCP in a routed environment. Now let's talk about the specifics of implementation of one of those things, which is configuring a DHCP relay agent. We defined it in the previous module but it's worth going over again very briefly. Here's our environment where we might need a relay agent, we've got a routed environment, two subnets, subnet1 and subnet2. We've got a DHCP server for handing out IP address but a router drops broadcast packets. So these guys are sending out discover packets looking for a DHCP server, how do we make sure that those discover packets get through? We implement a relay agent and we do it using the routing and remote access MMC snap-in. So this is not configured on a DHCP server but rather on a RRAS server, which is installed as a part of the Windows installation, this networking component and it's just a matter of configuring it, turning it on. When we do, we will specify an interface to listen on, so we'll select the interface where we're listening. And then we will say, all right now here's the IP address where I will then direct these discover packets to and turn them into directed IP datagrams. Now when you do this the other caveat here is that remember that the pool of addresses that work for subnet1 won't work for subnet2. So you need to configure two scopes on your DHCP server. How does this DHCP know which scope from scope1 or scope2 to hand out IP addresses? Well again when we use a DHCP relay agent, that relay agent appends the discover packet with its own network interface card's IP address. And that way by looking at the contents of that packet the DHCP server knows that the discover packet is coming from in this example subnet2. So we're going to offer a IP address from subnet2 to one of our clients. So that's how it all works. Let's actually do the button pushing now. The tool that we use to make this happen is routing and remote access. So under your administrative tools you should have this one installed by default. You shouldn't have to go out and install it but you can if it's not. The routing and remote access here, open it up, I've already got it open. The first time you use it and I've already got it configured, the first time you use it you'll have to configure it. We'll actually talk about that in the next module, so just stay tuned or you can just quickly do a custom configuration. But here's the button pushing I want to show you. Under the properties of your server, under the IP routing node because you're going to be routing IP packets here, You're going to right click the general and install a new routing protocol and the routing protocol we're going to install is DHCP agent. So that will then show up as another node under IP routing, DHCP relay agent, we specify the interface for the protocol to run on, so either the local area connection or internal interface, which are one and the same here, relay packets, hop count threshold, boot threshold, set from here and then once you have this configured, you will choose properties and then type in the server address. So let's say 192.168.5.10 that's the address of our DHCP server. So we're going to route this to that server, we're going to route discover packets to that server. So that's it, that's how you configure DHCP relay agent, so that you can implement DHCP in a routed environment even if you don't have a 1542 compliant router.