DHCP-Server - tell clients to renew lease

I have just set up a new DHCP server (dhcpd - package is dhcp3-server) on a Debian 6 box.
The new server is up and running, and I have successfully connected a client.

Formerly a router acted as the DHCP server.

My question: is there any way to send a broadcast to the network prompting all current lease holders - which still hold a lease from the router - to get a new lease from the new server?

Regards

Solution 1:

I don't believe there is a standard for recalling leases, since the lease time tells the client to hang on to the address until expiration.

If they're all in one switch, a work around is to power cycle the switch; most OSes will then renegotiate the lease, which would use the new DHCP server instead.