Change dhcp server IP address

[- Kone Bakenon -]

Hello all,
I run dhcp server on IPcop server and it's not working properly. My
network is subnetted in Vlan 3 and Vlan 4.
The first time when a computer is on Vlan 3 or 4, it takes a good
parameters but if the same computer is moved to another Vlan, only the IP
address of dhcp server is the same but all the parameters changes.
The IP address for dhcp server should be 172.16.0.1 on Vlan 3 and
172.16.16.1 on Vlan 4.
How can i change automaticaly the IP address for the server in this case.
Thanks for your help.
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Kone Bakenon K.
University of Ouagadougou
Burkina Faso
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