Wireless clients getting DHCP Server in a different subnet

Issue:

• Running "ipconfig /all" on the client shows that the wireless DHCP server is in a different subnet and/or a different DHCP server than expected;
• Confirmed no network connections observed from wireless client;
• Wireless network infrastructure consists of Lightweight Access Points controlled by Wireless LAN Controller (WLC);
• Even if IP address is released and renewed, client is still getting the correct IP address but DHCP Server is still in the different subnet.

#SNIPPET START

Wireless LAN adapter Wireless Network Connection:

   Connection-specific DNS Suffix  . : my.company.com

   Description . . . . . . . . . . . : Intel(R) Centrino(R) Advanced-N 6200 AGN

   Physical Address. . . . . . . . . : 00-27-EE-EE-EE-EE

   DHCP Enabled. . . . . . . . . . . : Yes

   Autoconfiguration Enabled . . . . : Yes

   Link-local IPv6 Address . . . . . : fe80::c010:5d39:eeee:eee%11(Preferred)

   IPv4 Address. . . . . . . . . . . : 10.100.30.228(Preferred)

   Subnet Mask . . . . . . . . . . . : 255.255.254.0

   Lease Obtained. . . . . . . . . . : Saturday, June 09, 2012 6:56:11 PM

   Lease Expires . . . . . . . . . . : Sunday, June 10, 2012 12:56:11 AM

   Default Gateway . . . . . . . . . : 10.100.30.1

   DHCP Server . . . . . . . . . . . : 192.168.1.1

   DHCPv6 IAID . . . . . . . . . . . : 218113808

   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-15-9D-76-61-00-EE-EE-EE-EE-EE

   DNS Servers . . . . . . . . . . . : 10.100.5.130

                                       10.100.5.132

                                       10.20.4.100

                                       10.20.4.80

   Primary WINS Server . . . . . . . : 10.100.30.209

   Secondary WINS Server . . . . . . : 10.100.30.210

   NetBIOS over Tcpip. . . . . . . . : Enabled

#SNIPPET END

Resolution:

• First thing to confirm is if there is any actual network issue; i.e., does the client have any network connectivity issues? In this example, it's already confirmed that there are no issues.
• In this case, there is actually no network/configuration issue; the WLC is configured as a DHCP Relay (as opposed to instead of as a DHCP Server); hence, the client sees a virtual IP address of the WLC, instead of the actual DHCP server.
• Here's the rough run-through of the process;
• Wireless Client DHCP request --> AP --> WLC (dhcp relay) ---> DHCP Server
• DHCP Server reply --> WLC --> AP --> Wireless Client

Reference:
Wireless LAN Controller (WLC) FAQ