IP issue

[Jun007]

Hi, 

Just want to ask few question about problem i have encountered.

I have core-SW 4500 series on this core-sw i have set my DHCP server. so far its working

but on some occasion, the user get incorrect IP.
(example: my local ip is 10.10.10.x sometimes the host pc would get 192.168.X.X)
 by the way after core-sw connection goes directly to access-sw which is a 2960 G series.

Thank you

[MHM Cisco World]

Vlan and dhcp broadcasts

if the client and core SVI “dhcp server in core sw” and the router then 

the client send broadcast the core sw and router receive it and hence both have dhcp pool they will assign ip according to 

for router the IP address of interface receive the broadcast 

the core sw the IP address of SVI of vlan of this broadcast

here if the core sw reply to client the client get right ip

if router reply to client the client get wrong ip !!!!

how if the router and core sw share same vlan broadcast domain with client.

what wrong is either router interface config with wrong vlan tag and hence 

or 

dot1x change the clan of client when it authorization 

or

there is op82 in dhcp request this op82 is use by router to assign ip for wireless clients this op82 is same send by wire client and this make router not depend on interface ip receive the broadcast but depend on op82 to assign ip.

the fast solution pack drop the dhcp request to router.