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I have multiple scopes on my dhcp server. 192.168.10.x and 192.168.20.x

I have reservations for certain mac addresses on the 192.168.10.x network. However occasionally they will pull 192.168.20.x addresses instead. There isn't per scope allow/deny filter so I can't force the server to not issues 192.168.20.x addresses to the 192.168.10.x machines.

What might be the problem? Or is this normal behavior?

lasmith
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    What's the subnet mask for the networks? Would a 192.168.10.x address be valid on the network on which 192.168.20.x is being assigned? – Adam Thompson Mar 17 '14 at 16:53
  • If you're serving multiple scopes then you must have multiple subnets. Do the affected clients move from one subnet to the other? – joeqwerty Mar 17 '14 at 18:58
  • Subnet mask is 255.255.255.0 and yes they seem to be moving from one subnet to the other. – lasmith Mar 17 '14 at 23:16

1 Answers1

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Silly question - VIRTUAL LANs, or physical LANs (2 physical NICs)? It may be as simple as the server doesn't know which scope you're coming in on.

Address assignment The DHCP server determines the scope to which a DHCP client belongs based on the gateway IP address of the relay agent or the interface of the DHCP server on which it receives the DHCP client packet. Once the server determines the client scope, the server evaluates the DHCP packet against the policies applicable for the scope in the processing order specified. The policies applicable at a scope are those configured at the scope and those inherited from the server. A single client request can match multiple policies.

Source: http://technet.microsoft.com/en-us/library/hh831538.aspx

Mike Rysanek
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