Network switching with Windows 2003 DHCP

I try to switch from network to as follows:
Existing win 2003 server with DHCP server has ip
added secondary ip address to it:
added new dhcp range , configured options, reservations etc.
Changed the max lease time from several days to a few minutes  and waited for the setting to propagate to clients
So far so good.
To switch networks I then disabled the old range and enabled
According to log, all old renewal requests fail (NACK), also after the max lease time. In fact it appears that the clients sooner or later give up. I don't see any leases issued by the new range at all.
After much more thanmax lease time, I disabled the new range and enabled the old range again; almostimmediately clients started to query and successfully obtain old range leases.

Why did the transition fail?
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Steve KnightConnect With a Mentor IT ConsultancyCommented:
In properties of the DHCP server, advanced tab there is a "bindings" button.  Maybe it is not bound to the other  address on there?   Other way may be to swap primary/secondary address on your IP settings.

thehagmanAuthor Commented:
I'm beginning to have a suspicion:
Even though the server has the ranges and a corresponding secondary) ip the dhcp server *listens* only on and hence can only serve a lease from (which is disabled).
Could tis be the cause?

If I don't find a nice idea here, I'll try to fool the system by configureing one of the switches with an ip-helper-address, i.e. a BOOTP relay from to

Steve KnightIT ConsultancyCommented:
What does
netstat -an | find ":67 "
show ... itshould show the UDP port 67 for DHCP.
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mcsweenSr. Network AdministratorCommented:
I think dragon-it has it with the bindings issue.
thehagmanAuthor Commented:
Yes, the binding shows only the primary IP. (Though IIRC, netstat showed !)
Steve KnightIT ConsultancyCommented:
Great, odd about the netstat though, I guess it was listening but ignoring?!
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