Lý do không nên triển khai MultiHome trên DC

Steps to avoid registering unwanted NIC(s) in DNS on a Mulithomed Domain Controller
http://support.microsoft.com/kb/2023004

Active Directory communication fails on multihomed domain controllers
http://support.microsoft.com/kb/272294

Lưu ý:
For multihomed servers, the DHCP service binds to the first IP address statically configured for each network connection in use.
By default, the service bindings depend on whether the first network connection is configured dynamically or statically for TCP/IP. Based on the method of configuration it uses, reflected by its current settings in Internet Protocol (TCP/IP) properties, the DHCP Server service performs default service bindings as follows:

• If the first network connection uses a manually specified IP address, the connection is enabled in server bindings. For this to occur, a value for IP address must be configured and the Use the following IP address option selected in Internet Protocol (TCP/IP) properties. In this mode, the DHCP server listens for and provides service to DHCP clients.
  
• If the first network connection uses an IP address configured dynamically, the connection is disabled in server bindings. This occurs when the Obtain an IP address automatically option is selected in Internet Protocol (TCP/IP) properties. For computers running Windows Server 2008 operating systems, this is the default setting. In this mode, the DHCP server does not listen for and provide service to DHCP clients until a static IP address is configured.
  
• The DHCP server will bind to the first static IP address configured on each adapter.

• By design, DHCP server bindings are enabled and disabled on a per-connection, not per-address basis. All bindings are based on the first configured IP address for each connection appearing in the Network Connections folder. If additional static IP addresses (for example, as set in Advanced TCP/IP properties) are configured for the applicable connection, these addresses are never used by DHCP servers running Windows Server 2008 and are inconsequential for server bindings. -> giải thích tại sai khi có 1 DHCP server khác (tích hợp trên router) kết nối chung với switch. Khi resart DHCP server -> DHCP kia sẽ take place
  
• DHCP servers running Windows Server 2008 never bind to any of the NDISWAN or DHCP-enabled interfaces used on the server. These interfaces are not displayed in the DHCP console under the current server bindings list because they are never used for DHCP service. Only additional network connections that have a primary static IP address configured can appear in the server bindings list (or be selectively enabled or disabled there).

http://technet.microsoft.com/en-us/library/cc770650.aspx



Multihomed DCs with DNS, RRAS, and/or PPPoE adapters

http://blogs.dirteam.com/blogs/acefekay/archive/2009/08/03/multihomed-dcs-with-dns-rras-and-or-pppoe-adapters.aspx

Thao luan
http://social.technet.microsoft.com/Forums/en-US/bbfdb2a2-38f7-4c4a-876d-f4922bf3013c/domain-controller-witch-2-nics-in-diferent-subnets?forum=winserverDS

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Khi IP hết, cân nhắc Resubnetting hoặc sử dụng Superscope

Resubnetting

This method requires you to change all subnet hosts and gateways. If you have an address range that has run out of available host addresses, you may be able to change the subnet mask to include a larger share of host addresses. However, simply changing the subnet mask requires that all routers and other statically assigned computers be reconfigured and all DHCP clients have renewed their lease obtaining the new parameters.

http://support.microsoft.com/kb/255999

Understand DHCP superscope 

http://bacutin.blogspot.com/2009/07/understand-dhcp-superscope.html

Using superscopes
http://technet.microsoft.com/en-us/library/cc757614(WS.10).aspx

Configuring a DHCP Superscope
http://technet.microsoft.com/en-us/library/dd759168.aspx

Step-by-step guide
http://www.techrepublic.com/article/create-a-superscope-to-solve-the-problem-of-dwindling-ip-addresses/#.

Recommended tasks for the DHCP server role
http://technet.microsoft.com/en-us/library/cc731392.aspx