UniFi Devices Offline After Update: Causes, Fixes, and Prevention

Published onby Iron (edited on )

When your UniFi devices suddenly go offline after an update, it feels like chaos. Your Wi-Fi is down, clients are calling, and you're left wondering what went wrong. Don’t panic. This issue happens to even the most experienced network admins. The good news? It’s usually easy to fix.

Let's dive in!

Table of Contents

Why Do UniFi Devices Go Offline After an Update?

During a UniFi update, several background processes kick in. Changes to IP addresses, DNS records, or controller links may seem minor, but they can disconnect devices. Here are the most common causes:

1. IP Address Changes

When your UniFi Controller or devices update, they might get assigned new IP addresses by the DHCP server. This change can confuse the controller, which is still looking for devices at the old IP addresses.

2. Inform URL Reset

The Inform URL tells UniFi devices where their controller is. Sometimes, an update resets this URL, causing devices to "forget" where to connect. Without this link, devices will show as "offline."

3. Firmware Mismatch

Your controller might update before your devices do. If the controller’s firmware is ahead of the devices' firmware, it may reject connections from older versions.

4. Adoption Issues

Updates can cause devices to “lose” their relationship with the controller. This is especially common with self-hosted controllers. Devices might show up as “Managed by Other” or “Adoption Failed.”

5. DNS Failures

If the controller can't resolve the IP addresses of devices due to a DNS misconfiguration, they’ll appear offline. DNS issues can happen when controller settings are updated or DNS cache is cleared during the update.

6. Firewall & Port Changes

Updates can modify which ports are used for device-to-controller communication. If your firewall doesn’t update to reflect these new port rules, devices will be blocked.

How to Get UniFi Devices Back Online

If you’re reading this, you probably have devices showing "offline." Don’t worry. Below are step-by-step instructions to troubleshoot and resolve this.

1. Reboot Everything

The classic “turn it off and on again” works for a reason. It forces devices to request new IPs, DNS records, and inform URLs.

Steps:

  1. Reboot your UniFi Controller.
  2. Power cycle UniFi devices (access points, switches, and routers) one by one.
  3. Wait for devices to reappear in the UniFi dashboard.

2. Verify Inform URL

If your devices don’t know where their controller is, they’ll remain offline. This is especially common if you self-host your controller.

How to Check:

  1. SSH into the device (you’ll need its IP address):
    ssh ubnt@<device-ip>
    
  2. Run this command to reconfigure the inform URL:
    set-inform http://<controller-ip>:8080/inform
    
  3. Check the controller’s Devices page. The device should now show up as "Pending Adoption." Adopt it.

Pro Tip: If you use a UniFi Cloud Controller, like UniHosted, the URL will be different. Check with your hosting provider for the correct URL format.

3. Check DHCP and DNS Settings

If devices get new IP addresses from the DHCP server during the update, they may no longer be reachable by the controller.

Steps:

  1. Check IP Addresses: Ensure devices are on the same subnet as the controller.
  2. Check DNS Server: Switch to 1.1.1.1 or 8.8.8.8 if you suspect DNS issues.
  3. Check IP Reservations: Make sure UniFi devices have IP reservations (static IPs) in your router settings.

Tool Tip: Use the UniFi WiFiman app to scan your network and identify devices' IPs.

4. Update Firmware Manually

If controller updates automatically, but your devices do not, they may fall out of sync.

Steps:

  1. Log into your controller and go to Devices.
  2. Look for devices with “Update Available” next to them.
  3. Click Update.

If devices are offline, use SSH to manually update the firmware:

  1. SSH into the device.
  2. Download and install the latest firmware:
    curl -O https://dl.ui.com/path/to/firmware.bin
    syswrapper.sh upgrade firmware.bin
    

Pro Tip: Get the latest firmware from the UniFi Update Guide.

5. Reset Devices to Factory Defaults

If nothing works, you may need to start from scratch.

Steps:

  1. Press the reset button on the device for 10 seconds.
  2. It will reboot and clear all settings.
  3. Re-adopt it in the UniFi Controller.

How to Prevent Devices from Going Offline After Updates

Now that your devices are back online, let’s make sure this never happens again.

1. Schedule Updates for Off-Hours

Updates often cause brief disconnections, so schedule them for 3 AM.

How:

  1. Go to Settings > System in the UniFi Controller.
  2. Schedule updates during non-peak hours (like 3 AM).

2. Use Static IPs

Prevent IP conflicts and make sure devices never get "lost" by DHCP.

How:

  1. Go to Devices in the controller.
  2. Click on each device, select Settings, and assign it a static IP.

3. Enable Backups

Automatic backups will save you hours of headaches if something breaks.

How:

  1. Go to Settings > Backups.
  2. Turn on Daily Backups.

Pro Tip: If you use UniHosted, cloud backups are automatic.

4. Use a Cloud Controller

If you’re tired of fixing issues after every update, consider a cloud-hosted UniFi Controller. Cloud controllers like UniHosted handle updates for you.

Why Use UniHosted?

  • Automatic Backups: Never lose your configuration.
  • Automatic Updates: Devices stay in sync with the controller.
  • Custom URL: Your devices always know where to "phone home."

Try UniHosted for free at UniHosted.

5. Use Inform URL Best Practices

To avoid inform URL issues, ensure devices are using the correct URL after every update.

How:

  1. Set static IPs for controllers and use DNS names.
  2. Use the "Override Inform Host" setting in the UniFi Controller.

6. Monitor DNS & Port Changes

When controller settings change, DNS and firewall rules might break.

Checklist:

  • DNS: Use Google DNS (8.8.8.8) or Cloudflare DNS (1.1.1.1).
  • Ports: Open TCP/UDP ports: 443, 8080, 8443, and 3478.

FAQs

Q1: How Do I Know If My Inform URL is Correct?

Log into the device via SSH and run:

info

Look for "Inform URL". If it’s wrong, set it with:

set-inform http://<controller-ip>:8080/inform

Q2: What If My Device Says "Managed by Other"?

This happens when the device is linked to an old controller. Either factory reset the device or "Forget" it from the old controller.

Q3: Why Does My UniFi Controller Lose Connection?

If the controller has a dynamic IP, the inform URL may be invalid. Switch to a static IP.

Final Thoughts

When your UniFi devices go offline after an update, it’s not the end of the world. Usually, it’s one of three things: DHCP issues, firmware mismatches, or inform URL problems. Use the steps in this guide to bring devices back online quickly.

If you’re done dealing with update headaches, consider using UniFi Controller. We handle updates, backups, and DNS settings for you. No more late nights troubleshooting! If you would like me to personally walk you through UniHosted, you can schedule a call with me here.

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