Dhcp not updating a records in dns predating tucson
I also noted a staggering amount of old, outdated DNS records.
Scavenging appeared to be configured, but not actually working.
Here is an example of the SECONDS field being set to 6 in a DHCP network packet.
- Dhcp: Request, Msg Type = DISCOVER, Transaction ID = 0x BCBCFAE3 Op Code: Request, 1(0x01) Hardwaretype: Ethernet Hardware Address Length: 6 (0x6) Hop Count: 0 (0x0) Transaction ID: 3166501603 (0x BCBCFAE3) Flags: 32768 (0x8000) Client IP: 0.0.0.0 Your IP: 0.0.0.0 Server IP: 0.0.0.0 Relay Agent IP: 0.0.0.0 Client Hardware Address: 00-12-3F-17-E0-CF Server Host Name: Boot File Name: Magic Cookie: 99.1 Message Type: DISCOVER - Type 53 Auto Configure: Auto Configure (1) - Type 116 client ID: (Type 1) - Type 61 Requested IPAddress: 10.0.0.3 - Type 50 DHCPEOptions Host Name: DHCPEOptions Vendor Class Identifier: Parameter Request List: - Type 55 End: Padding: Binary Large Object (5 Bytes) The last interesting behavior we saw on this case was that the client device was switching DHCP Transaction IDs between the DISCOVER and the REQUEST.
Under the SOA tab, the refresh interval is 15 minutes, retry is 10, and the expiration is 1 day. There are no DNS events in the log which suggest that something is set up wrong.
DHCP is set as follows: Enable DNS dynamic updates - always dynamically update DNS A and PTR records.
Here is my config for DHCP on the switch -ip dhcp pool PC network 10.1.70.0 255.255.255.0 domain-name dns-server 10.1.1.1 10.1.1.2 default-router 10.1.70.1 lease 8This is an office across the street from the main building.The network trace looked something like this: DHCP: Request, Msg Type = DISCOVER, Transaction ID = 0x BCBCFAE3 DHCP: Reply, Msg Type = OFFER, Transaction ID = 0x BCBCFAE3 DHCP: Request, Msg Type = REQUEST, Transaction ID = 0x BCBCFAE4 DHCP: Reply, Msg Type = ACK, Transaction ID = 0x BCBCFAE4 If you see behavior like this with a DHCP client, contact the DHCP client vendor and see if they have an update to resolve the behavior as this is non-RFC compliant. In this case, the customer simply disabled BOOTP on the client device, since it wasn’t enabled on the DHCP server anyway.After this change, only the DHCP server that owned the client lease would respond and we no longer had issues with DNS records being removed.Note: DHCP failover does not support for BOOTP in Windows Server 2012 RTM, but DHCP failover does support BOOTP in Windows 2012 R2.Here is a screenshot of BOOTP being disabled on the scope.