Contents
Introduction
Prerequisites
Requirements
Components Used
Conventions
Background Information
Configure
Network Diagram
Configure the WLC for Basic Operation
Configure the Switch for the WLC
Configure the Switch for the APs
Verify
Troubleshoot
Commands
Controller Does Not Defend AP-Manager IP Address
Troubleshoot a Lightweight Access Point Not Joining a Wireless LAN Controller
Introduction
This document provides a basic configuration example of a lightweight access point (AP) that is connected to a Cisco Wireless LAN (WLAN) Controller (WLC) through a Cisco Catalyst Switch.
Prerequisites
Requirements
Ensure that you meet these requirements before you attempt this configuration:
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Basic knowledge of the configuration of lightweight APs and Cisco WLCs
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Basic knowledge of Lightweight AP Protocol (LWAPP)
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Knowledge of the configuration of an external DHCP server and/or domain name server (DNS)
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Basic configuration knowledge of Cisco switches
Components Used
The information in this document is based on these software and hardware versions:
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Cisco Aironet 1232AG Series Lightweight AP
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Cisco 4402 Series WLC that runs firmware 5.2.178.0
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Microsoft Windows Server 2003 Enterprise DHCP server
This configuration works with any other Cisco WLC and any lightweight AP.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Conventions
Refer to the Cisco Technical Tips Conventions for more information on document conventions.
Background Information
In order for the WLC to be able to manage the LAP, the LAP should discover the controller and register with the WLC. There are different methods that an LAP uses in order to discover the WLC. For detailed information on the different methods the LAPs use to register to the WLCs, refer to Lightweight AP (LAP) Registration to a Wireless LAN Controller (WLC)
This document describes the configuration steps needed to register the LAP to the WLC and for basic operation of the LWAPP wireless network.
Configure
In order to register the LAP to the WLC and for basic operation of the LWAPP wireless network, complete these steps:
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Have a DHCP server present so that the APs can acquire a network address.
Note: Option 43 is used if the APs reside in a different subnet.
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Register the lightweight APs to the WLCs.
Note: Use the Command Lookup Tool (registered customers only) in order to obtain more information on the commands used in this section.
Network Diagram
This document uses this network setup:
Configure the WLC for Basic Operation
When the controller boots at factory defaults, the bootup script runs the configuration wizard, which prompts the installer for initial configuration settings. This procedure describes how to use the configuration wizard on the command-line interface (CLI) in order to enter initial configuration settings.
Note: Be sure that you understand how to configure an external DHCP server and/or DNS.
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Connect your computer to the WLC with a DB-9 null modem serial cable.
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Open a terminal emulator session with these settings:
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9600 baud
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8 data bits
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1 stop bit
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No parity
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No hardware flow control
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At the prompt, log in to the CLI.
The default username is admin, and the default password is admin.
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If necessary, enter reset system in order to reboot the unit and start the wizard.
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At the first wizard prompt, enter a system name. The system name can include up to 32 printable ASCII characters.
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Enter an administrator user name and password. The user name and password can include up to 24 printable ASCII characters.
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Enter the service-port interface IP configuration protocol, either none or DHCP.
Enter none if you do not want to use the service port or if you want to assign a static IP address to the service port.
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If you entered none in step 7 and need to enter a static IP address for the service port, enter the service-port interface IP address and netmask for the next two prompts.
If you do not want to use the service port, enter 0.0.0.0 for the IP address and netmask.
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Enter values for these options:
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Management interface IP address
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Netmask
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Default router IP address
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Optional VLAN identifier
You can use a valid VLAN identifier or 0 for untagged.
Note: When the management interface on the controller is configured as part of the 'native vlan' on the switchport to which it connects, the controller should NOT tag the frames. Therefore, you must set the VLAN to be zero (on the controller).
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Enter the Network Interface (Distribution System) Physical Port number.
For the WLC, the possible ports are 1 through 4 for a front-panel gigabit Ethernet port.
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Enter the IP address of the default DHCP server that supplies IP addresses to clients, the management interface, and the service-port interface, if you use one.
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Enter the LWAPP Transport Mode, either LAYER2 or LAYER3.
Note: If you configure the WLC 4402 via Wizard and select AP transport Mode LAYER2, the Wizard does not ask the details of AP Manager.
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Enter the Virtual Gateway IP Address.
This address can be any fictitious, unassigned IP address, such as 1.1.1.1, for the Layer 3 Security and Mobility managers to use.
Note: Usually the Virtual Gateway IP Address that is used is a private address.
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Enter the Cisco WLAN Solution Mobility Group/RF Group name.
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Enter the WLAN 1 service set identifier (SSID) or network name.
This identifier is the default SSID that lightweight APs use in order to associate to a WLC.
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Allow or disallow Static IP Addresses for clients.
Enter yes in order to allow clients to supply their own IP addresses. Enter no in order to require clients to request an IP address from a DHCP server.
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If you need to configure a RADIUS server on the WLC, enter yes and enter this information:
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RADIUS server IP address
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The communication port
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The shared secret
If you do not need to configure a RADIUS server or you want to configure the server later, enter no.
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Enter a country code for the unit.
Enter help in order to see a list of the supported countries.
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Enable and disable support for IEEE 802.11b, IEEE 802.11a, and IEEE 802.11g.
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Enable or disable radio resource management (RRM) (auto RF).
Complete these steps in order to configure the WLC for basic operation:
WLC 4402—Configuration Wizard |
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Welcome to the Cisco Wizard Configuration Tool Use the '-' character to backup System Name [Cisco_43:eb:22]: c4402 Enter Administrative User Name (24 characters max): admin Enter Administrative Password (24 characters max): ***** Service Interface IP Address Configuration [none][DHCP]: none Enable Link Aggregation (LAG) [yes][NO]: No Management Interface IP Address: 192.168.60.2 Management Interface Netmask: 255.255.255.0 Management Interface Default Router: 192.168.60.1 Management Interface VLAN Identifier (0 = untagged): 60 Management Interface Port Num [1 to 2]: 1 Management Interface DHCP Server IP Address: 192.168.60.25 AP Transport Mode [layer2][LAYER3]: LAYER3 AP Manager Interface IP Address: 192.168.60.3 AP-Manager is on Management subnet, using same values AP Manager Interface DHCP Server (192.168.50.3): 192.168.60.25 Virtual Gateway IP Address: 1.1.1.1 Mobility/RF Group Name: RFgroupname Network Name (SSID): SSID Allow Static IP Addresses [YES][no]: yes Configure a RADIUS Server now? [YES][no]: no Enter Country Code (enter 'help' for a list of countries) [US]: US Enable 802.11b Network [YES][no]: yes Enable 802.11a Network [YES][no]: yes Enable 802.11g Network [YES][no]: yes Enable Auto-RF [YES][no]: yes |
Note: The management interface on the WLC is the only consistently pingable interface from outside of the WLC. So it is an expected behavior if you are not able to ping the AP manager interface from outside of the WLC.
Note: You must configure the AP manager interface in order for the APs to associate with the WLC.
Configure the Switch for the WLC
This example uses a Catalyst 3750 switch that uses only one port. The example tags the AP-manager and management interfaces and places these interfaces on VLAN 60. The switch port is configured as an IEEE 802.1Q trunk and only the appropriate VLANs, which are VLANs 2 through 4 and 60 in this case, are allowed on the trunk. The management and AP-manager VLAN (VLAN 60) is tagged and is not configured as the native VLAN of the trunk. So when the example configures those interfaces on the WLC, the interfaces are assigned a VLAN identifier.
This is an example 802.1Q switch port configuration:
interface GigabitEthernet1/0/1 description Trunk Port to Cisco WLC switchport trunk encapsulation dot1q switchport trunk allowed vlan 2-4,60 switchport mode trunk no shutdown
Note: When you connect the WLC gigabit port, make sure it is connected to the switch gigabit port only. If you connect the WLC gigabit Ethernet to the Switch FastEthernet port then it will not work.
Notice that this configuration example configures the neighbor switch port in a way that only allows relevant VLANs on the 802.1Q trunk. All other VLANs are pruned. This type of configuration is not necessary, but it is a deployment best practice. When you prune irrelevant VLANs, the WLC only processes relevant frames, which optimizes performance.
Configure the Switch for the APs
This is an example VLAN interface configuration from the Catalyst 3750:
interface VLAN5 description AP VLAN ip address 10.5.5.1 255.255.255.0
While the Cisco WLCs always connect to 802.1Q trunks, Cisco lightweight APs do not understand VLAN tagging and should only be connected to the access ports of the neighbor switch.
This is an example switch port configuration from the Catalyst 3750:
interface GigabitEthernet1/0/22 description Access Port Connection to Cisco Lightweight AP switchport access vlan 5 switchport mode access no shutdown
The infrastructure is now ready for connection to the APs. The LAPs use the different WLC discovery methods and select a WLC to join. The LAP then registers with the controller.
Verify
Use this section in order to confirm that your configuration works properly.
After the LAPs register with the controller, you can view them under Wireless at the top of the user interface of the controller:
On the CLI, you can use the show ap summary command in order to verify that the LAPs registered with the WLC:
(Cisco Controller) >show ap summary Number of APs.................................... 1 Global AP User Name.............................. Not Configured Global AP Dot1x User Name........................ Not Configured AP Name Slots AP Model Ethernet MAC Location Port Country Priority ------------------ ----- ------------------- ----------------- ---------------- ---- ------- ------ AP001b.d4e3.a81b 2 AIR-LAP1232AG-A-K9 00:1b:d4:e3:a8:1b default location 2 IN 1
On the WLC CLI, you can also use the show client summary command in order to see the clients that are registered with the WLC:
(Cisco Controller) >show client summary Number of Clients................................ 1 MAC Address AP Name Status WLAN Auth Protocol Port ----------------- ------------- ------------- ---- ---- -------- ---- 00:40:96:a1:45:42 ap:64:a3:a0 Associated 4 Yes 802.11a 1 (Cisco Controller) >
Here is a video demonstration that explains how to perform the initial configuration of a Wireless LAN Controller using the GUI and CLI: Initial Configuration of Wireless Lan Controller using CLI and GUI
Troubleshoot
Use this section in order to troubleshoot your configuration.
Commands
Use these commands in order to troubleshoot your configuration.
Note: Refer to Important Information on Debug Commands before you use debug commands.
This debug lwapp events enable WLC command output shows that the lightweight AP gets registered to the WLC:
(Cisco Controller) >debug lwapp events enable Tue Apr 11 13:38:47 2006: Received LWAPP DISCOVERY REQUEST from AP 00:0b:85:64:a3:a0 to ff:ff:ff:ff:ff:ff on port '1' Tue Apr 11 13:38:47 2006: Successful transmission of LWAPP Discovery-Response to AP 00:0b:85:64:a3:a0 on Port 1 Tue Apr 11 13:38:58 2006: Received LWAPP JOIN REQUEST from AP 00:0b:85:64:a3:a0 to 00:0b:85:33:a8:a0 on port '1' Tue Apr 11 13:38:58 2006: LWAPP Join-Request MTU path from AP 00:0b:85:64:a3:a0 is 1500, remote debug mode is 0 Tue Apr 11 13:38:58 2006: Successfully added NPU Entry for AP 00:0b:85:64:a3:a0 (index 48) Switch IP: 192.168.60.2, Switch Port: 12223, intIfNum 1, vlanId 60 AP IP: 10.5.5.10, AP Port: 19002, next hop MAC: 00:0b:85:64:a3:a0 Tue Apr 11 13:38:58 2006: Successfully transmission of LWAPP Join-Reply to AP 00:0b:85:64:a3:a0 Tue Apr 11 13:38:58 2006: Register LWAPP event for AP 00:0b:85:64:a3:a0 slot 0 Tue Apr 11 13:38:58 2006: Register LWAPP event for AP 00:0b:85:64:a3:a0 slot 1 Tue Apr 11 13:39:00 2006: Received LWAPP CONFIGURE REQUEST from AP 00:0b:85:64:a3:a0 to 00:0b:85:33:a8:a0 Tue Apr 11 13:39:00 2006: Updating IP info for AP 00:0b:85:64:a3:a0 -- static 0, 10.5.5.10/255.255.255.0, gtw 192.168.60.1 Tue Apr 11 13:39:00 2006: Updating IP 10.5.5.10 ===> 10.5.5.10 for AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: spamVerifyRegDomain RegDomain set for slot 0 code 0 regstring -A regDfromCb -A Tue Apr 11 13:39:00 2006: spamVerifyRegDomain RegDomain set for slot 1 code 0 regstring -A regDfromCb -A Tue Apr 11 13:39:00 2006: spamEncodeDomainSecretPayload:Send domain secret Mobility Group<6f,39,74,cd,7e,a4,81,86,ca,32,8c,06,d3,ff,ec,6d,95,10,99,dd> to AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Successfully transmission of LWAPP Config-Message to AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Running spamEncodeCreateVapPayload for SSID 'SSID' Tue Apr 11 13:39:00 2006: AP 00:0b:85:64:a3:a0 associated. Last AP failure was due to Configuration changes, reason: operator changed 11g mode Tue Apr 11 13:39:00 2006: Received LWAPP CHANGE_STATE_EVENT from AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Successfully transmission of LWAPP Change-State-Event Response to AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Received LWAPP Up event for AP 00:0b:85:64:a3:a0 slot 0! Tue Apr 11 13:39:00 2006: Received LWAPP CONFIGURE COMMAND RES from AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Received LWAPP CHANGE_STATE_EVENT from AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Successfully transmission of LWAPP Change-State-Event Response to AP 00:0b:85:64:a3:a0 Tue Apr 11 13:39:00 2006: Received LWAPP Up event for AP 00:0b:85:64:a3:a0 slot 1!
This output shows these useful WLC debug commands:
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debug pem state enable —Configures the access policy manager debug options
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debug dhcp message enable —Shows the debug of DHCP messages that are exchanged to and from the DHCP server
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debug dhcp packet enable —Shows the debug of DHCP packet details that are sent to and from the DHCP server
Tue Apr 11 14:30:49 2006: Applied policy for mobile 00:40:96:a1:45:42 Tue Apr 11 14:30:49 2006: STA [00:40:96:a1:45:42, 192.168.1.41] Replacing Fast Path rule type = Airespace AP Client on AP 00:0B:85:64:A3:A0, slot 0 InHandle = 0x00000000, OutHandle = 0x00000000 ACL Id = 255, Jumbo Frames = NO, interface = 1 802.1P = 0, DSCP = 0, T Tue Apr 11 14:30:49 2006: Successfully plumbed mobile rule for mobile 00:40:96:a1:45:42 (ACL ID 255) Tue Apr 11 14:30:49 2006: Plumbed mobile LWAPP rule on AP 00:0b:85:64:a3:a0 for mobile 00:40:96:a1:45:42 Tue Apr 11 14:30:53 2006: DHCP proxy received packet, src: 0.0.0.0, len = 320 Tue Apr 11 14:30:53 2006: dhcpProxy: Received packet: Client 00:40:96:a1:45:42 DHCP Op: BOOTREQUEST(1), IP len: 320, switchport: 1, encap: 0xec03 Tue Apr 11 14:30:53 2006: dhcpProxy(): dhcp request, client: 00:40:96:a1:45:42: dhcp op: 1, port: 1, encap 0xec03, old mscb port number: 1 Tue Apr 11 14:30:53 2006: dhcp option len, including the magic cookie = 84 Tue Apr 11 14:30:53 2006: dhcp option: received DHCP REQUEST msg Tue Apr 11 14:30:53 2006: dhcp option: skipping option 61, len 7 Tue Apr 11 14:30:53 2006: dhcp option: requested ip = 192.168.1.41 Tue Apr 11 14:30:53 2006: dhcp option: skipping option 12, len 15 Tue Apr 11 14:30:53 2006: dhcp option: skipping option 81, len 19 Tue Apr 11 14:30:53 2006: dhcp option: vendor class id = MSFT 5.0 (len 8) Tue Apr 11 14:30:53 2006: dhcp option: skipping option 55, len 11 Tue Apr 11 14:30:53 2006: dhcpParseOptions: options end, len 84, actual 84 Tue Apr 11 14:30:53 2006: mscb->dhcpServer: 192.168.60.2, mscb->dhcpNetmask: 255.255.255.0,mscb->dhcpGateway: 192.168.60.1, mscb->dhcpRelay: 192.168.60.2 VLAN: 60 Tue Apr 11 14:30:53 2006: Local Address: 192.168.60.2, DHCP Server: 192.168.60.2, Gateway Addr: 192.168.60.2, VLAN: 60, port: 1 Tue Apr 11 14:30:53 2006: DHCP Message Type received: DHCP REQUEST msg Tue Apr 11 14:30:53 2006: op: BOOTREQUEST, htype: Ethernet, hlen: 6, hops: 1 Tue Apr 11 14:30:53 2006: xid: 3371152053, secs: 0, flags: 0 Tue Apr 11 14:30:53 2006: chaddr: 00:40:96:a1:45:42 Tue Apr 11 14:30:53 2006: ciaddr: 0.0.0.0, yiaddr: 0.0.0.0 Tue Apr 11 14:30:53 2006: siaddr: 0.0.0.0, giaddr: 192.168.60.2 Tue Apr 11 14:30:53 2006: Forwarding DHCP packet locally (348 octets) from 192.168.60.2 to 192.168.60.2 Tue Apr 11 14:30:53 2006: Received 348 byte dhcp packet from 0x0201a8c0 192.168.60.2:68 Tue Apr 11 14:30:53 2006: DHCP packet: 192.168.60.2 -> 192.168.60.2 using scope "InternalScope" Tue Apr 11 14:30:53 2006: received REQUEST Tue Apr 11 14:30:53 2006: Checking node 192.168.1.41 Allocated 1144765719, Expires 1144852119 (now: 1144765853) Tue Apr 11 14:30:53 2006: adding option 0x35 Tue Apr 11 14:30:53 2006: adding option 0x36 Tue Apr 11 14:30:53 2006: adding option 0x33 Tue Apr 11 14:30:53 2006: adding option 0x03 Tue Apr 11 14:30:53 2006: adding option 0x01 Tue Apr 11 14:30:53 2006: dhcpd: Sending DHCP packet (giaddr:192.168.60.2)to 192.168.60.2:67 from 192.168.60.2:1067 Tue Apr 11 14:30:53 2006: sendto (548 bytes) returned 548 Tue Apr 11 14:30:53 2006: DHCP proxy received packet, src: 192.168.60.2, len = 548 Tue Apr 11 14:30:53 2006: dhcpProxy: Received packet: Client 00:40:96:a1:45:42 DHCP Op: BOOTREPLY(2), IP len: 548, switchport: 0, encap: 0x0 Tue Apr 11 14:30:53 2006: dhcp option len, including the magic cookie = 312 Tue Apr 11 14:30:53 2006: dhcp option: received DHCP ACK msg Tue Apr 11 14:30:53 2006: dhcp option: server id = 192.168.60.2 Tue Apr 11 14:30:53 2006: dhcp option: lease time (seconds) = 86400 Tue Apr 11 14:30:53 2006: dhcp option: gateway = 192.168.60.1 Tue Apr 11 14:30:53 2006: dhcp option: netmask = 255.255.255.0 Tue Apr 11 14:30:53 2006: dhcpParseOptions: options end, len 312, actual 64 Tue Apr 11 14:30:53 2006: DHCP Reply to AP client: 00:40:96:a1:45:42, frame len 412, switchport 1 Tue Apr 11 14:30:53 2006: DHCP Message Type received: DHCP ACK msg Tue Apr 11 14:30:53 2006: op: BOOTREPLY, htype: Ethernet, hlen: 6, hops: 0 Tue Apr 11 14:30:53 2006: xid: 3371152053, secs: 0, flags: 0 Tue Apr 11 14:30:53 2006: chaddr: 00:40:96:a1:45:42 Tue Apr 11 14:30:53 2006: ciaddr: 0.0.0.0, yiaddr: 192.168.1.41 Tue Apr 11 14:30:53 2006: siaddr: 0.0.0.0, giaddr: 0.0.0.0 Tue Apr 11 14:30:53 2006: server id: 1.1.1.1 rcvd server id: 192.168.60.2
You can use these additional debug commands in order to troubleshoot your configuration:
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debug lwapp errors enable—Shows output of the debug of LWAPP errors
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debug pm pki enable—Shows the debug of certificate messages that are passed between the AP and the WLC
Controller Does Not Defend AP-Manager IP Address
This issues is a result of bug CSCsg75863. If the user accidently injects a device on the subnet that uses the AP-manager IP address of the controller, the Address Resolution Protocol (ARP) cache on the default gateway router is refreshed with the wrong MAC address. When this occurs, the APs can no longer reach the controller and drop into their discovery phase to look for a controller. The APs send discovery requests, and the controller responds with discovery replies, but the JOIN requests never reach the AP-manager interface of the controller because of the bad ARP entry on the gateway router. After the default 4 hour ARP refresh interval, the APs join the controller if the device is removed.
A workaround for this issue is to configure the static ARP entries on the gateway router of the controller for these IP addresses:
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Management IP address—Customers gain access to the graphical user interface (GUI) from another subnet, and the controller receives the AP discovery requests.
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AP-Manager IP address—APs join the controller from another subnet.
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Every Dynamic interface IP address—Packets from other subnets reach the dynamic interface of the controller.
DHCP packets transmit from the interface of the wireless client. Telnet or SSH to the gateway address of the controller, and use the arp <ip address> <hhhh.hhhh.hhhh> command in order to add the ARP entries. Use the ping command on the default router of the controller to the different addresses in order to refresh the ARP cache on the router. In order to discover the MAC addresses, use this command: show arp | include <ip address>.
Troubleshoot a Lightweight Access Point Not Joining a Wireless LAN Controller
Refre to Troubleshoot a Lightweight Access Point Not Joining a Wireless LAN Controller for information on some of the issues why a Lightweight Access Point (LAP) fails to join a WLC and how to troubleshoot the issues.