The DHCP server in Windows Server 2008 R2 has invested in the areas of security, reliability, manageability and usability. Similarly on the DHCP Client in Windows 7 has invested on certain optimization for obtaining IP Address.
The following changes are available in DHCP server in Windows Server 2008 R2:
· Supports MAC address based network access control mechanism, with the Link Layer based Filtering feature. With this feature DHCP Administrator can control issuance/denial of DHCP leases/IP addresses.
· Supports prevention of name squatting issues caused due to non-Windows OS machines, with the Name Protection feature. Using this feature one could prevent registration of non-Windows OS machine with a same name that is already registered for another machine in DNS Server.
· Supports prevention of exhaustion of IP addresses at scope level especially for the deployments catering to redundancy/high-availability scenarios like Split-Scope. This feature is available only for IPv4 network and not for IPv6 network as in case of latter exhaustion of addresses is not an issue.
· Supports DHCP activity logging, allows DHCP Administrators to monitor the configuration changes of the DHCP Servers. DHCP Administrators would use this feature for network security / IT compliance auditing purposes.
· Supports migration of DHCP Server role using Windows Server Migration Tool (WSMT).
· DHCP Server service is moved under Network Service account from Local Service account. With this the DHCP Server service that runs in the context of the Network Service account presents the computer's credentials to remote servers. Also the advantage with Network Service is it has very few privileges and can do less damage on the server if compromised.
· Usability and operability enhancements of DHCP Server like:
- Auto-population of certain network interface fields like DNS Server addresses (both IPv4 and IPv6), WINS Server addresses, during installation and configuration of scope.
- Interpretive Icons for better readability.
- Wizard based split-scope configuration for ease and error free split-scope deployment.
- Address leases to filter (multiple select supported) for ease of Link Layer based filter configuration for leased clients.
- Address leases to reservation (multiple select supported) for ease of reservation configuration for leased clients.
- In the product scenario/task based help content for Windows Server 2008 R2 features.
· Supports DHCPv6 Option 15 (User Class). This is used by client to identify the type or category of user or application it represents. It involves both DHCP Server and Client side implementation.
· Support of DHCPv6 Option 32 (Information Refresh Time). This specifies an upper bound for how long a client should wait before refreshing information retrieved from DHCPv6. It involves both DHCP Server and Client side implementation.
· Better performance and scalability achieved through lease database caching. Read more about it here.
The DHCP client of Windows 7 has support for optimization to obtain IP Address using SSID caching.
· Supports SSID caching so that, laptop devices with Windows 7 could get IP Address in a lesser time in a Wireless LAN network during revisits to the same.
· Extended NDF and unified tracing to support additional scenario.
· Broadcast bit flag behaviour is updated to toggle between ‘0’ and ‘1’ and also would cache the last successful broadcast bit setting for which the client received IP Address. This way it would ensure the client to acquire the address properly, irrespective of the support for the flag by the 3rd party DHCP Server \ Relay Agent.
· Support of DHCPv6 Option 32 (Information Refresh Time). This specifies an upper bound for how long a client should wait before refreshing information retrieved from DHCPv6.