Windows server dhcp relay agent

DHCP now supports option 82 sub-option 5. You can use these options to allow DHCP proxy clients and relay agents to request an IP address for a specific subnet, and from a specific IP address range and scope. The Link Selection Sub option of option 82 is useful in this situation, allowing the relay agent to explicitly state the subnet from which it wants the IP address allocated in the form of DHCP v4 option 82 sub option 5.

A special scope can be created to "authorize" relay agents. You referred that the DHCP server hold two scopes, but you have three subnets. Is subnet 3 At last I wonder if you have modified the value of hop count threshold, 4 by default.

Subnet 2 is the link between Routers 1 and 2 Interfaces. You can manually edit route table, add route entries in order to make subnet 1 could be able to communicate with subnet 3. The communication should be two-way communicate. Give it a try and check if it works. In fact, a better way to make it work you can move DHCP server to subnet 2. Or you can connect subnet 3 directly to subnet 1. For more information, please refer to the sticky post. Office Office Exchange Server.

Not an IT pro? Microsoft Online Services TechCenter. Sign in. United States English. Ask a question. Quick access. Search related threads. Remove From My Forums. Answered by:.

Archived Forums. Windows Server General Forum. Sign in to vote. Monday, June 29, PM. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. PBA enables targeted administration and greater control of the configuration parameters delivered to network devices with DHCP. A subnet has a mix of different types of clients: desktop computers, printers, IP phones, and other devices.

You want different types of clients to get IP addresses from different IP address ranges within the subnet. This is possible using DHCP policies if the devices have different vendors. For example:. By specifying a different IP address range for different device types, you can more easily identify and manage devices on the network. In a subnet which has a mix of wired and mobile computers, you might want to assign a shorter, 4 hour lease duration to mobile computers and longer, 4 day lease duration to wired computers.

Employees bring in their own devices such as smartphones and tablets to work and you want to manage network traffic or control network access based on device type. You want to provide a different set of scope options to different types of devices. Polices are configured at the scope level to control IP address range and at the server level to specify lease duration.

Based on the vendor class and MAC prefix values provided, the client request matches conditions of policy A3. After all scope polices are processed, server level policies are processed and the client also matches conditions of policy 1. After all policies are processed, the DHCP server returns an IP address configuration to the client using the settings specified in policies A3 and 1.

It is assigned the first available IP address in the IP address range In Windows Server R2 and previous operating systems, if you want to specify the IP address range for a specific set of clients or devices, or assign different option values based on device type, the only way to achieve this is to configure a scope with individual reservations.

This method can require high effort, and is difficult to manage on an ongoing basis. See Policy processing to understand how settings are applied when they are configured in multiple policies, in reservations, at the scope level, or at the server level.

You can define a single policy, or several. Characteristics of DHCP policies include:. Policy level : Polices can apply at the server level or the scope level.