[Best Practices] Use server-side conflict detection on DHCP servers only when it is needed RRS feed

  • Question

  • Conflict detection can be used by either DHCP servers or clients to determine whether an IP address is already in use on the network before leasing or using the address. 

    DHCP client computers running Windows 2000 or Windows XP that obtain an IP address use a gratuitous ARP request to perform client-based conflict detection before completing configuration and use of a server offered IP address. If the DHCP client detects a conflict, it will send a DHCP decline message (DHCPDECLINE) to the server. 

    If your network includes legacy DHCP clients (clients running a version of Windows earlier than Windows 2000), you can use server-side conflict detection provided by the DHCP Server service under specific circumstances. For example, this feature might be useful during failure recovery when scopes are deleted and recreated. By default, the DHCP service does not perform any conflict detection. To enable conflict detection, you can increase the number of ping attempts that the DHCP service performs for each address before leasing that address to a client. Note that for each additional conflict detection attempt that the DHCP service performs, additional seconds are added to the time needed to negotiate leases for DHCP clients. 

    Typically, if DHCP server-side conflict detection is used, you should set the number of conflict detection attempts made by the server to one or two pings at most. This provides the intended benefits of this feature without decreasing DHCP server performance. 

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    Tuesday, October 16, 2018 7:43 AM