badders Posted March 7, 2012 Posted March 7, 2012 We have a strange problem with our DHCP server (Server 2008 R2), in the DHCP console the IPv4 icon is displaying a blue circle with an exclamation mark. According to Microsoft this means that our scope is fully used up, but looking at the statistics 73% of addresses are available. I've stopped and restarted the DHCP service on the server but it has mad eno difference. Is there anything else I can try?
TheMinister Posted March 7, 2012 Posted March 7, 2012 Check current address leases. There might be a few bad_addresses which are sitting on an IP address but don't count within the statistics. Solution: Increase your DHCP scope.
badders Posted March 7, 2012 Author Posted March 7, 2012 There were a few bad_addresses but only about 5 or 6. There are plenty of ip addresses still available, 617 used 1687 available.
badders Posted March 7, 2012 Author Posted March 7, 2012 Just deleted some exclusion ranges and stopped and restarted DHCP again and now have a nice green tick, still not sure why I didn't when the exclusion ranges were present. I might try re-adding the exclusions and see if it breaks again.
badders Posted March 7, 2012 Author Posted March 7, 2012 It's now back to the blue exclamation, anybody have any ideas of what else I can try?
TheMinister Posted March 7, 2012 Posted March 7, 2012 Are your exclusions taking up a significant portion of your DHCP leases?
badders Posted March 8, 2012 Author Posted March 8, 2012 Not now, I've removed them all apart from one range of 254 addresses, which still leaves of 1500 addresses available.
badders Posted March 8, 2012 Author Posted March 8, 2012 A few errors in event log relating to dhcp. Event ID:1056 The DHCP service has detected that it is running on a DC and has no credentials configured for use with Dynamic DNS registrations initiated by the DHCP service. This is not a recommended security configuration. Credentials for Dynamic DNS registrations may be configured using the command line "netsh dhcp server set dnscredentials" or via the DHCP Administrative tool. Event ID:1070 Iashlpr initialization failed: The DHCP service was unable to access path specified for the audit log. , so DHCP server cannot talk to NPS server. It could be that IAS service is not started. Event ID:10020 This computer has at least one dynamically assigned IPv6 address.For reliable DHCPv6 server operation, you should use only static IPv6 addresses.
TheMinister Posted March 8, 2012 Posted March 8, 2012 10020: Are you using IPv6? If not, this error is fine. 1070: Do you have Network Access Protection enabled or disabled? If enabled, you have a problem. Try disabling it. 1056: Check that DHCP can dynamically update DNS. Check which user DHCP server service is running under. Should be 'Network Service' 1
badders Posted March 9, 2012 Author Posted March 9, 2012 Not using IPv6, DHCP server service is running as Network Service (still have warning 1056), we're not using NAP but I disabled it on the scope and that seems to have fixed the problem. I'll keep an eye on it for a while and see what happens, looking good so far.
badders Posted March 9, 2012 Author Posted March 9, 2012 Looks like it was the NAP settings, not been any more problems today.
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