ISC DHCP server always ACKs DHCPREQUESTs without checking the server identier

Fri Feb 23 11:50:02 UTC 2007

I am using the ISC DHCP server version 3.0.5. Most of the DHCP clients 
on my network have host declarations with fixed adresses. I have noticed 
that the server  sends DHCPACK messages to clients requesting (via 
DHCPREQUEST) leases from other DHCP server. I have looked at the source 
code and have noticed that the server identier in DHCPREQUEST messages 
is not used. I'm wondering why the server behaves like that.