Clients dropping when renewing dhcp address

Here's my top tip for the week.. After reconfiguring my dhcp server from scratch I couldn't work out why my clients were losing their network connectivity at the same time as their dhcp lease was up. It turned out I'd forgotten the LeaseNeg symbol.

From http://docs.sun.com/app/docs/doc/802-5753/6i9g71m6q?a=view
The LeaseNeg symbol determines whether or not a client can renegotiate its lease with the server before the lease expires. If this symbol is present, then the client can renegotiate its lease. LeaseNeg allows clients to operate on the network without lease-related interrupts of existing connections.

doh!