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Troubleshoot AP Disconnection Issues

SUMMARY Read this topic to understand how you can troubleshoot issues that cause an access point (AP) to disconnect from the cloud. The blink pattern of the LED on the AP can help you identify the problem. Table 1 lists the LED behavior for some of the common issues that cause an AP to disconnect from the network.

Table 1: Troubleshoot AP Disconnection Issues
LED Color Blink Pattern Issue Steps to Troubleshoot
Off The AP is not receiving power.

  1. Check whether the switch port connected to the AP learns the MAC address of the AP.

  2. Check the power logs on the AP to verify that PoE is enabled on the switch port.

  3. Check whether the switch is supplying power to the AP. Change the cable and the switch port to see whether the AP powers on.

  4. If you have a working AP, swap it with the faulty AP. Check whether the issue persists.

    Note:

    If your APs are already installed and you cannot swap any AP, skip this step.
Blinking green and yellow for more than 30 seconds The AP is trying to connect to the Juniper Mist™ cloud but is unable to connect.

  1. Verify that the relevant ports are open on the firewall. See Firewall Configuration.

  2. Connect a laptop to the same switch port as the AP. Open https://ep-terminator.mistsys.net/about and see if it resolves the host.

    Your output should look like this:

    {
"version": "0.3.4476",
"git-commit": "0db544d97d09c21dd2ea0778c1f6d03465861c9d",
"build-time": "2020-03-16_23:45:06_UTC",
"go-runtime": "go1.14",
"env": "production",
"procname": "ep-terminator/🌧/provider=aws/env=production/host=ep-terminator-172-31-16-17-762f638f-production.mistsys.net/pid=12226/user=terminator",
"start-time": "2020-03-19T01:32:54Z",
"uptime": 707675.367648
}

  3. Check the firewall logs to see whether any policy is blocking the https://ep-terminator.mistsys.net/about URL.
Blinking yellow two times The switch or AP is experiencing a Layer 2 issue.

  1. Run a cable test to verify that the cable connected to the AP is working correctly.

  2. Check whether the switch port connected to the AP learns the MAC address of the AP.

  3. Check for any eth0 errors on the switch port.

  4. Change the cable and switch port and verify that the AP powers on.

  5. If you have a working AP, swap it with the faulty AP. Check whether the issue persists.

    Note:

    If your APs are already installed and you cannot swap any AP, skip this step.
Blinking yellow three times The AP is unable to obtain an IP address.

The AP can obtain an IP address either through DHCP or through a static configuration.

Troubleshooting steps for DHCP:

  1. Check whether the switch port configuration has the required parameters (such as native VLAN and VLAN ID) configured.

  2. Check the DHCP server logs to verify that leases are available in the DHCP pool.

  3. Connect a laptop to the switch port to which the AP was connected. Verify that the laptop is able to obtain an IP address from the VLAN management pool.

    • If the laptop is unable to obtain an IP address, contact the DHCP team to fix the DHCP pool. You can port-mirror the switch port to identify which step in the DHCP Discover, Offer, Request, Acknowledgment (DORA) process is failing.

    • If your laptop is able to obtain an IP address whereas the AP is unable to obtain an IP address, contact the Juniper support team.

Troubleshooting steps for static configuration:

If the AP was connected to the Juniper Mist cloud earlier, check the static configuration on the Juniper Mist portal. If the static configuration is incorrect, then the AP will not be able to connect to the Juniper Mist cloud. To correct the static configuration:

  1. Power off the AP by shutting down the PoE on the switch connected to the AP. Alternatively, you can remove the physical cable that provides power to the AP.

  2. Correct the configuration on the switch port.

  3. Reset the AP to the factory-default configuration. See Reset an Access Point to the Factory-Default Configuration.

  4. Power on the AP.
Blinking yellow four times No default gateway IP address found in the DHCP lease or static configuration.

  1. Check the DHCP pool configuration to see whether the default gateway is configured.

  2. If you've configured a static IP address for the AP, check whether the default gateway is configured correctly.

    If the default gateway is not configured correctly, follow these steps:

    1. Power off the AP by shutting down the PoE on the switch port to which the AP is connected. Alternatively, you can remove the physical cable that provides power to the AP.

    2. Correct the configuration on the switch port.

    3. Reset the AP to the factory-default configuration. See Reset an Access Point to the Factory-Default Configuration.

    4. Power on the AP.

  3. Perform port mirroring for the switch port and obtain the packet capture. In the DHCP offer packet from the server, check whether the default gateway field displays an IP address.

    • If the default gateway field does not display an IP address, contact your DHCP server team to fix the configuration on the DHCP server.

    • If the default gateway field displays an IP address, contact Juniper Mist support to troubleshoot the issue.

Blinking yellow five times The default gateway IP address is configured but the AP is unable to connect to the default gateway.

  1. Verify that the default gateway IP address is set correctly in all the configurations on the switch port (VLAN, native VLAN) and the DHCP pool configuration.

  2. If you've configured a static IP address for the AP, check whether the default gateway is configured correctly.

    If the default gateway is not configured correctly, follow these steps:

    1. Power off the AP by shutting down the PoE on the switch port to which the AP is connected. Alternatively, you can remove the physical cable that provides power to the AP.

    2. Correct the configuration on the switch port.

    3. Reset the AP to the factory-default configuration. See Reset an Access Point to the Factory-Default Configuration.

    4. Power on the AP.

    If the configuration is correct and the LED still blinks yellow five times, follow these steps:

    1. Connect a laptop on the same VLAN, network, or switch port to which the AP was connected.

    2. Ping the default gateway. Use the ipconfig /all command to get the default gateway information.

      If the ping fails, contact your network administrator to check for issues on the wired side.

      If the ping succeeds but the AP still fails to connect, contact Juniper Mist support.
Blinking yellow six times No DNS IP address found in the DHCP lease or static configuration.

  1. Check the DHCP pool configuration to see whether the DNS server is configured.

  2. If you've configured a static IP address for the AP, check whether the DNS server is configured correctly.

    If the DNS server is not configured correctly, follow these steps:

    1. Power off the AP by shutting down the PoE on the switch port to which the AP is connected. Alternatively, you can remove the physical cable that provides power to the AP.

    2. Correct the configuration on the switch port.

    3. Reset the AP to the factory-default configuration. See Reset an Access Point to the Factory-Default Configuration.

    4. Power on the AP.

  3. Perform port mirroring for the switch port and obtain the packet capture. In the DHCP offer packet from the server, check whether the dns server field displays an IP address.

    • If the dns server field does not display an IP address, contact your DNS server team to fix the configuration on the DNS server.

    • If the dns server field displays an IP address, contact Juniper Mist support to troubleshoot the issue.

Blinking yellow seven times The DNS server does not respond to a DNS lookup. The AP receives the DNS server through DHCP but it cannot reach or ping the Juniper Mist™ cloud. When the AP gets an IP address from the DHCP server, the AP tries to reach ep-terminator.mistsys.net. If the DNS server is unable to resolve this URL, the AP cannot connect to the cloud.

  • Connect a laptop on the same VLAN or network, and try to resolve the URL ep-terminator.mistsys.net to an IP address by executing the nslookup command at the command prompt.

    C:\Users\username>nslookup ep-terminator.mistsys.net
Server: dns.google
Address: 8.8.8.8
Non-authoritative answer:
Name: ep-term-production-1584483204-1989267174.us-west-1.elb.amazonaws.com
Addresses: 52.9.76.55
13.57.102.113
Aliases: ep-terminator.mistsys.net

  • If the nslookup command cannot resolve the URL, explicitly add the URL to your DNS server.

  • If the issue is still not resolved, check the firewall and proxy logs to see whether the traffic for the URL is getting dropped. You can also take a packet capture to analyze further.

Need Help?

If you're unable to resolve the issue after following the steps listed in the table, contact Juniper support or open a support ticket.

Provide the following details to customer support:

  • What is the exact LED blink pattern that you see on the AP? You can also share a short video of the blinking pattern.

  • Are you getting the MAC address of the AP on your switch port?

  • Is the AP receiving power from the switch?

  • Is the AP getting an IP address and pinging on the Layer 3 gateway of your network?

  • What are the troubleshooting steps that you followed?

  • Are there any additional logs that can help identify the root cause of the issue?

Note:

If you select the Allow Mist Support Team to access your Mist Organization option on the Support Access tile in Organization Settings (Organization > Settings), the Mist support personnel can see all the device information available through the Mist portal.