I keep these errors over and over again in my DHCP logs:

354 : Get type:5, IPAddr:10.96.11.45, LeaseTime:0, MacIndx:311, pIP:0
AMAGet() exit err:8, subnet:10.96.11.0, addr:10.96.11.45
2005/10/14 15:17:23 <DHCPREQUEST> packet received from client <0:30:6E:2F:93:3F>, client requested IP address = <10.96.11.45>.
2005/10/14 15:17:23 DHCP Warning: There is no matching entry configured for client <0:30:6E:2F:93:3F>.
2005/10/14 15:17:23 Sending BOOTP/DHCP reply <DHCPNAK> to <0:30:6E:2F:93:3F> as <10.96.11.1>.
359 : Get type:5, IPAddr:10.96.11.45, LeaseTime:0, MacIndx:311, pIP:0
AMAGet() exit err:8, subnet:10.96.11.0, addr:10.96.11.45
2005/10/14 15:17:28 <DHCPREQUEST> packet received from client <0:30:6E:2F:93:3F>, client requested IP address = <10.96.11.45>.
2005/10/14 15:17:28 DHCP Warning: There is no matching entry configured for client <0:30:6E:2F:93:3F>.
2005/10/14 15:17:28 Sending BOOTP/DHCP reply <DHCPNAK> to <0:30:6E:2F:93:3F> as <10.96.11.1>.

I've searched around but haven't found a good explanation for it. Any ideas?

Thanks.