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DHCP Statistics disagree between fail over servers and actual leases. RRS feed

  • Question

  • Is this something that a Reconcile should fix?

    We have two Server 2012 R2 DHCP servers in a Hot Standby Failover configuration. DHCP1 (active), and DHCP2 (Partner)

    DHCP1 is frequently low or out of available addresses.  It's statistics show:
    Total Addresses: 256
    In Use: 243
    Available: 13
    Add. Available In this Server's Pool: 8
    Add. Available In Partner's Pool: 5
    Add. Granted by this Server: 243
    Add. Granted by Partner: 0

    DHCP2 tells a different story however. It's statistics show:

    Total Addresses: 256
    In Use: 164
    Available: 92
    Add. Available In this Server's Pool: 5
    Add. Available In Partner's Pool: 87
    Add. Granted by this Server: 0
    Add. Granted by Partner: 164

    Using powershell to export the leases to a CSV file shows 158 actual leases. And given the size of our company, this is a fairly accurate number.

    There are no exclusions setup in that address range, and I'm unable to ping any of the 79 unaccounted for addresses. I'm hoping a reconcile will fix this, but have never performed one and don't want to make a situation worse.


    Tuesday, April 12, 2016 11:04 PM

Answers

  • Doing a Reconcile on the active server's scope found 81 inconsistencies and repaired them.  I believe this has resolved our issue.
    • Marked as answer by Derek R S Thursday, April 14, 2016 3:34 PM
    Thursday, April 14, 2016 3:34 PM

All replies

  • Hi Derek R S,

    Could you provide the screenshot of using command "netsh dhcp server show mibinfo" both on active DHCP server and partner DHCP server. We may compare the result with statistics results on both servers. (If you didn't refresh the statistics, don't forget to refresh the statistics first).

    Besides, can you find any errors in the DHCP event log or do you have specific issue when clients lease address from DHCP server? I have ever met some similar cases that after configuring DHCP hot standby mode, the DHCP statistics don't match the actual lease situation, while I didn't find official article to report that it is a bug.

    Best Regards,

    Anne


    Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Support, contact tnmff@microsoft.com.

    Wednesday, April 13, 2016 6:40 AM
    Moderator
  • There are lots of 20287 event errors (Scope out of IP addresses) logged, but that's it.  The problem we are having is that the DHCP server frequently thinks it is out of IPs and so fails to issue addresses to clients, but when you take a closer look at the leases, there should be 70-80 addresses available for lease.

    Here is the output for the command.  As you can see both servers agree on the 172.16.35 scope, but the 172.16.86 scope has different results on each server.  I tend to believe the stats on the Standby server are the correct ones.

    Active:
    MIBCounts:
            Discovers = 233745.
            Offers = 230784.
            Delayed Offers = 0.
            Requests = 8695.
            Acks = 157948.
            Naks = 236.
            Declines = 7.
            Releases = 3.
            ServerStartTime = Thursday, March 31, 2016 8:28:15 AM
            Scopes = 2.
            Scopes with Delay configured= 0.
            Subnet = 172.16.xxx.0.
                    No. of Addresses in use = 119.
                    No. of free Addresses = 129.
                    No. of pending offers = 0.
            Subnet = 172.16.yyy.0.
                    No. of Addresses in use = 235.
                    No. of free Addresses = 21.
                    No. of pending offers = 1.
    Standby:
    MIBCounts:
            Discovers = 236986.
            Offers = 32.
            Delayed Offers = 0.
            Requests = 7948.
            Acks = 139865.
            Naks = 95.
            Declines = 7.
            Releases = 0.
            ServerStartTime = Thursday, March 31, 2016 8:21:05 AM
            Scopes = 2.
            Scopes with Delay configured= 0.
            Subnet = 172.16.xxx.0.
                    No. of Addresses in use = 119.
                    No. of free Addresses = 129.
                    No. of pending offers = 0.
            Subnet = 172.16.yyy.0.
                    No. of Addresses in use = 156.
                    No. of free Addresses = 100.
                    No. of pending offers = 0.


    • Edited by Derek R S Thursday, April 14, 2016 3:33 PM
    Wednesday, April 13, 2016 3:22 PM
  • Doing a Reconcile on the active server's scope found 81 inconsistencies and repaired them.  I believe this has resolved our issue.
    • Marked as answer by Derek R S Thursday, April 14, 2016 3:34 PM
    Thursday, April 14, 2016 3:34 PM