Windows 2008 R2 DHCP server not responding to DHCP discover
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            by MartinSteel
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        Published on 2010-05-28T11:32:00Z
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            2010/05/28
            11:42 UTC
        
        
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dhcp
|windows-server-2008-r2
I've got two Windows 2008 Enterprise R2 servers both running DNS and DHCP called cod & lobster. DHCP is setup using the split scope option introduced with 2008 R2, whereby both servers should respond with the first response providing the lease. Setup is as follows:
Cod
 - IP: 192.168.0.231
 - Pool: 192.168.0.101 - 192.168.0.179, exclusion for 160-179.
 - Response Delay: 0ms
 - Authorised in Active Directory (Re-authorised to confirm)
 - Windows firewall disabled while testing
Lobster
 - IP: 192.168.0.232
 - Pool: 192.168.0.101 - 192.168.0.179, exclusion for 101-159.
 - Response Delay: 1000ms
 - Authorised in Active Directory
All DHCP leases to clients are currently being issues by Lobster rather than Cod. Packet captures with Wireshark show the following (all to broadcast address):
Client - DHCP Discover
Lobster - DHCP Offer (after 1s delay)
Client - DHCP Request
Lobster - DHCP Ack
Client - DHCP Inform
From my setup with two servers I'd expect to see a DHCP Offer coming from Cod almost immediately after the DHCP Discover.
Does anybody have any idea what would prevent the DHCP Server responding to the discover?
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