DHCP Reservations and STatic IP's RRS feed

  • Question

  • What happens if you have a static ip on the machine for a teamed nic and create a reserveration in dhcp but the mac at some point changes because of failover,etc. What happens if mac in a reservation changes?
    Wednesday, May 9, 2018 5:40 PM

All replies

  • Hi,

    In a cluster, each computer (or cluster node) has a network adapter attached to the corporate network, and each cluster node has its own IP address, network name (NetBIOS name), and MAC address.
    The virtual server has an IP address and network name, but uses the MAC address of the cluster node that is the current owner of the virtual server resources.

    When a failover occurs, the cluster server of the node that is receiving IP resources sends a gratuitous ARP request so that all devices (computers, routers, and switches) are updated, and a new MAC address is assigned to an existing IP address.
    If a switch or router does not pass the updated MAC-to-IP address mappings, other network devices contain the old MAC address for the cluster node that is down.

    Hope this is to any help.

    Kind regards,

    Don't forget to visit my blog The System Center Blog

    Wednesday, May 9, 2018 7:48 PM
  • To clarify we have teamed NICs used as primary/standby and upon reboots the IP changes and the MAC being used changes as at any time the secondary can become primary and vice versa. So what is the best way to create a DHCP reservation for this? If i create a reservation for the IP and 1 mac but the mac changes will that become a problem or will DHCP never hand out that IP regardless of whether MAC is correct or not..
    Thursday, May 10, 2018 5:58 PM