Configure the DHCP Relay Agent

Membership in the local Administrators group, or equivalent, is the minimum required to complete this procedure.

1.  first we have to install RRAS from   server mgr >> add roles. and install it.  
2. Open the Routing and Remote Access MMC snap-in.
   
3. In the console tree, expand the server name, and then expand IPv4.
   
4. Under IPv4, right-click General, and then select New Routing Protocol.
   
5. Select DHCP Relay Agent, and then click OK.
   
6. Right-click DHCP Relay Agent, and then select New Interface.
   
7. Select the interface that corresponds to the VPN server’s LAN adapter, and then click OK.
   
8. On the General tab, make sure that Relay DHCP packets is selected and then, if necessary, select values for Hop-count threshold and Boot threshold.
   
   
9. Click OK.
   
10. Repeat steps 5 through 8 for the interface to which the remote access clients connect.