Microsoft dhcp helper

Alternatively, the router can forward these requests as directed broadcasts to a specific network or subnetwork. In interface configuration mode, use the ip helper-address command to define the address to which UDP broadcasts for services should be forwarded.

By default, the ip helper-address command forwards the eight UDP services listed in Table below. What if Company XYZ needs to forward requests for a service not on this list? The Cisco IOS software provides the global configuration command ip forward-protocol to allow an administrator to forward any UDP port in addition to the default eight. This command is used not only to add a UDP port to the default eight, but also to subtract an unwanted service from the default group.

Consider the complex sample helper address configuration shown in Figure What is needed in this example is a helper address configuration that relays broadcasts to all servers on the segment. The following commands configure a directed broadcast to the IP subnet that is being used as a server farm:. Configuring a directed broadcast to the server segment, Configure the RTA e0 to make it work by adding the command ip helper-address Verify the correct helper configuration with the show ip interface command, as shown in Example Notice that the RTA interface e3 in Example , which connects to the server farm, is not configured with helper addresses.

However, the output shows that for this interface, directed broadcast forwarding is disabled. This means that the router does not convert the logical broadcast To allow all the nodes in the server farm to receive the broadcasts at Layer 2, configure e3 to forward directed broadcasts with the following commands:.

Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. How IP helper address works? But this depends on the host, DHCP server, and if the requested address is available. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. Asked 1 year, 7 months ago. Active 1 year, 7 months ago. Viewed times. Improve this question. Thomas G. Lau Thomas G. Lau 1 1 gold badge 4 4 silver badges 13 13 bronze badges. The DHCP servers built into network devices are really minimal, and you should not use them if you have a real DHCP server or even any minimally complex situations. Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services.

Privacy policy. Without DHCP, IP addresses for new computers or computers that are moved from one subnet to another must be configured manually; IP addresses for computers that are removed from the network must be manually reclaimed. With DHCP, this entire process is automated and managed centrally. Because the IP addresses are dynamic leased rather than static permanently assigned , addresses no longer in use are automatically returned to the pool for reallocation.

The DHCP server stores the configuration information in a database that includes:. Valid IP addresses, maintained in a pool for assignment to clients, as well as excluded addresses. The lease duration, or the length of time for which the IP address can be used before a lease renewal is required.