Hi,

For now, I have a physical network with his DNS (bind) (one zone: iii.cccccc.bb - network 89.bb.cc.dd/xx).

But maybe, I will must split his network on 2 physical network with a router/firewall for communicate between theses 2 network (maybe 3).

So, I must have one DNS server for two network with a ip address range:
89.bb.cc.dd/xx
AND
10.gg.hh.jj/xx

Exameple : un client computer pc.iii.cccccc.bb (ip: 89.gg.hh.ii) will communicate with a database db1.iii.cccccc.bb (ip 10.gg.hh.jj).

Can I have one zone (iii.cccccc.bb) with different ip address for serve my networks ?

DNS does not care. The giant multi-national corporation example.com has offices all over the world with many different IPs all served from one zone by ns.example.com.