AX150 not able to connect wireless Clients

[Stex898]

Hello everyone,
I'm fairly new to the Cisco universe and hope you can help me with a problem I can't quite understand.

A customer of mine has the following setup: Cisco C1111-4P router and a CBS 350 series Switch. He now wanted to connect two AX150 access points to this Switch. The problem is that no wireless client can connect to the SSID of the APs. The status LED changes from green to blue, but after about a minute the client disconnects with an error message. I can see on the test clients that they receive a DHCP address of 169.254.xxx.xxx, so I assume there is a DHCP problem. Now to the strange part: When I unplug the AP at the switch port and plug in my notebook, I immediately get a correct DHCP address and Internet access. If I then plug the AP back in, I can also access the AX150 APs' management website from the LAN without any problems.

As a test, I then established a connection to the relevant SSID on a wireless client and then assigned myself a static IP address, but it was still not possible to connect to the LAN.

For information: The IP traffic runs via a VLAN, which is available as access ports on the switch.

Does a special DHCP configuration have to be made in the interaction between the Cisco router, switch and access point or can the error be located elsewhere?

Of course, it would be perfect if one of you people already knows this problem and could help me.

Many thanks for your ideas and best regards from Germany

[marce1000]

        >... but after about a minute the client disconnects with an error message
                         - What is the error message ?
                         + Check the logs on the AP upon client connection(s) and 'follow these' until the client disconnects

       >... address of 169.254.xxx.xxx, so I assume there is a DHCP problem.
            Looks like it because that is link local address (indeed) : On the intended configuration check if you can ping
            the configured DHCP server on the AP for instance.

        >...plug in my notebook, I immediately get a correct DHCP address and Internet access
             From other clients too ? Looks more like a false positive to me ; how can the notebook provide internet
             access from wireless clients on the AP.

       >...Does a special DHCP configuration have to be made in the interaction between the Cisco router
            It depends if the DHCP server is not directly reachable on the WLAN/VLAN pair that is configured on the AP for 
            wireless clients
           then the VLAN must be setup on the switch using a DHCP Relay statement to  point to the ip  address of the DHCP 
           server , so then clients on that VLAN can get a response from the DHCP server too.

 M.

[Stex898 · Accepted solution]

Thank you for the information.
I found out that it was due to the static management IP of the AX150. As soon as I changed this to DHCP, there was no longer a problem.

[adam543snell]

Hello,

Certainly! Let’s troubleshoot the issue with your Cisco setup. It sounds like there might be a configuration issue related to DHCP or VLANs. Here are some steps you can take to diagnose and potentially resolve the problem:

Check VLAN Configuration:
Ensure that the VLAN configuration on the CBS 350 switch is correct. Make sure the VLAN associated with the AX150 access points is properly configured and assigned to the relevant switch ports.
Verify that the VLAN tagging (if used) matches between the switch and the access points.
Verify DHCP Configuration:
Confirm that the DHCP server is correctly configured on the CBS 350 switch. The CBS 350 series supports DHCP server functionality, so you can configure it directly on the switch.
Check the DHCP pool settings for the VLAN associated with the AX150 access points. Ensure that the pool has sufficient IP addresses available and that the correct subnet mask is configured.
You can use the following commands on the switch to configure DHCP pools:
To configure a DHCP static address on a DHCP server and enter the DHCP Pool Host Configuration mode:
switchxxxxxx(config)# ip dhcp pool host aaaa
switchxxxxxx(config-dhcp)# address 10.12.1.99 255.255.255.0 client-identifier 01b7.0813.8811.66
switchxxxxxx(config-dhcp)# exit

To configure the subnet number and mask for a DHCP address pool on a DHCP server (network pool):
switchxxxxxx(config)# ip dhcp pool network bbbb
switchxxxxxx(config-dhcp)# address 10.12.1.88 255.255.255.0 hardware-address 00:01:b7:08:13:88
switchxxxxxx(config-dhcp)# exit

Check Access Point Configuration:
Verify that the AX150 access points are correctly configured with the appropriate SSID and security settings.
Ensure that the access points are connected to the correct VLAN on the switch.
Debugging and Logs:
Use debugging tools on the switch to check for any DHCP-related issues. You can analyze logs or use Wireshark to capture DHCP traffic between the access points and the switch.
Look for any anomalies in DHCP requests and responses.
Additionally, check if the access points are correctly associated with the WLC (Wireless LAN Controller) and if they are receiving the correct configuration.
SSID Configuration:
Make sure that the SSID configurations match across all access points. Verify that the SSID profiles are correctly associated with the appropriate VLANs and security settings.
Client-Side Troubleshooting:
On the client side, ensure that the wireless network adapter drivers are up to date.
Try disabling the “AX” mode if you’re using a Wi-Fi 6 router. Older wireless network adapters might not detect the Wi-Fi 6 network properly.
Check if the clients are getting valid IP addresses from DHCP. You mentioned that clients receive 169.254.xxx.xxx addresses, which indicates APIPA (Automatic Private IP Addressing). This usually occurs when the client cannot reach the DHCP server. Verify that the DHCP server is reachable from the access points.
Remember to document your changes and test each step to identify the root cause. If you continue to experience issues, consider reaching out to Cisco support or consulting with a network specialist. Good luck with your troubleshooting

I’ve provided detailed troubleshooting steps to help you resolve the issue. If you need further assistance or have additional questions, feel free to ask.

Best Regards

adam543