Hello,
I want to continue with the innovations in the previous DHCP service.
1. DHCPv4:
· The most important change compared to previous versions is the addition of settings for NAP interaction.
2. DHCPv6:
· DHCP service supports IPv6 addresses with Windows Server 2008. In this addressing model separated into Stateful and Stateless It is decided whether the client will create the address itself or get it from the DHCP server..
· In Stateful mode, clients can obtain necessary configuration information along with their IP addresses by using only DHCPv6 server..
· In stateless mode, it allows clients to create their own IP addresses and request only the necessary configuration information from the DHCP server.. In this, an IP address is created using a specific prefix over a Router that supports IPv6 stateful..
3. MAC Address based filtering (R2 only)
· Control of response of IP lease requests at MAC address level can now be done at Link Layer level.
· This feature can only be defined on Windows Server 2008 R2 DHCP server. However, it is not required under the DHCP client scope.. Available for all Windows and non-Windows operating systems.
· Only applicable for IPv4 addresses.
· Operations such as DISCOVER, RENEW and INFORM in the DHCP protocol will be subject to this rule.. However, DHCPINFORM packets sent by other DHCP servers and used to identify Rogue DHCP servers are excluded from this scope.. Thus, these requests sent by another DHCP server will be accepted whether they are in the list we filter at the MAC address level or not..
· The Filters tab can be used in IPv4 scope properties to enable this feature. Enable Allow List and Enable Deny List Two different list definitions can be made, (Enable Red List).
· All network hardware types except “Ethernet” are exempted. In Advanced in the>Properties/Filters tab other exempted network types can be added..
· After enabling from the Properties/Filters tab, a new section will be created on the DHCP console named Filters scope. According to the definition made from the properties, the “Allow” and “Deny” lists can be defined here. Also this section can be used to enable or disable a specific list..
· Characters such as ‘*’ can be used in the list where MAC addresses will be created. However, it is necessary to be careful with its use, because a client that needs an IP address may be included in the RED list by using the wrong ‘*’..
4. Service Hardening (R2 only)
Windows Server 2008 R2 DHCP service has less authority than other groups It is run with the “Network Service” account..
5. Split Scope (R2 Only)
· Since the first day of using DHCP servers, relatively more clients have been It is a method practiced by many network administrators to configure more than one DHCP server with a specific rule/rate for the same address range, in environments where there is a. The general purpose of this method, which is generally called the 80/20 rule, is to ensure that a certain rate of an IP range is given by the primary DHCP server and the other by the secondary DHCP server, while limiting the IP ranges within the framework of the rules..
· Until Windows Server 2008 R2, to make such a configuration, it was necessary to define scopes, specify the IP range, and define exclusions on both servers.. Now, the intervals that will be used by both servers can be easily made from a single window.. I copied the screenshot for reference:
6. Prevention of Exhaustion of IP Addresses (R2 only)
· Added feature to prevent running out of IP address range. It can only be used for IPv4 addresses as there is no such problem for IPv6 addresses.
· Particularly in environments with split scope configured, secondary DHCP servers, Configure button and Enable Name Protection should be selected in the newly opened window. After the selection, the options in the DNS tab will be disabled..
8. Activity Logging (R2 Only)
· “Activity” in addition to Audit logs used since 2000 logging has been enhanced. It is used to control DHCP servers serving in different sites, buildings and even on different floors, and especially to follow the changes to be made by people with DHCP Administrator privileges..
· On which DHCP server and with which Administrator account the changes were made Applications and Services Logs > Microsoft > Windows > DHCP Server > Microsoft-Windows-DHCP Server Events/Operational
9. DHCPv6 Option15 and Option32 (R2 and Windows7 only)
· Added two new options for DHCPv6:
o Option 15 (User Class) : This option used by the DHCP client shows which user or application type it supports.. It can be used by both DHCP server and DHCP client.
o Option 32 (Information Refresh Time): To DHCPv6 configuration Specifies how long the client will wait for the information to be refreshed.. It can be used by both DHCP server and DHCP client.
Also DHCP Some features have been added on the “wizard” used in the installation of the service and adding the scope, which will facilitate the operations of the administrators..
In addition, the use of memory and its control for accessing the database used by the DHCP server have been increased. Windows Server 2008 R2 aims to reduce file I/O by storing the DHCP database (Jet Database) in memory as in previous versions.. Memory usage is more intense in R2 and if desired, how much memory the server will use can be controlled via the registry.. By default, the DHCP server determines how many resources to use.. Although the upper and lower levels can be determined with the HKEY_LOCAL_MACHINESYSTEMCurrentControlSetservicesDHCPServerParametersJetDatabaseMaxCacheSize key, I advise you not to change the default values.. For administrators who are concerned about how much resources the DHCP server can use, I’d like to share data from the DHCP test suite’s testing..
6 GB RAM’ Added 2,000,000 active leased clients on a DHCP server running on 2 Dual Core AMD 64 bit 2.2 with I. While this system can make 1500 new rentals per second, it can also make 7400 renewals per second.. In such an environment, the size of the database was only 875 MB, while the portion kept in memory was 660 MB.. In summary, the probability of encountering a performance problem in systems that will only be used as a DHCP server is not more than errors that may occur in your RAM or Disks..
Quote: Technet
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