This article will provide suggestions for troubleshooting and resolving issues with slow Wi-Fi speeds on your UniFi network, as well as better understand what Wi-Fi speeds to expect and how to optimize your Wi-Fi configuration. 

• Introduction
• Measuring Wi-Fi performance
• Prerequisites
• Common Issues/Steps to Fix

Introduction

One of the most common Wi-Fi performance concerns reported is slower than expected Wi-Fi speed. This is due to a number of factors: 

• Speed issues can result from a wide range of network limitations and problems, many of which have nothing to do with wireless.
• Declined speed is easy to notice in typical network usage.
• Internet speed tests are the most widely—and sometimes the only tool used to evaluate/benchmark network performance: and can be inconsistent and inaccurate. 
• ISPs and hardware vendors market products with peak theoretical performance that differ from real-life usage. 

Measuring Wi-Fi Performance 

When looking at Wi-Fi performance it is important to take a step back and consider how Wi-Fi is supposed to work. Wi-Fi offers the benefit of mobility, scalability, and convenience over wired networks at the expense of maximum throughput and stability. With respect to client performance, modern Wi-Fi is designed to allow clients to enjoy the benefits of not being tethered to a wired network while preventing any visible reduction in performance across its area of coverage.  

Much of the concern about wireless throughput comes from a lack of understanding about how much bandwidth clients actually use. The difference between 300 Mbps and 500 Mbps may seem significant but the difference in performance would likely never be noticed through client use.

Here are estimated requirements of what throughput client devices need to use without declined performance (for more info see here): 

Client Application-specific Bandwidth Requirements

UniFi’s products are designed and tested to ensure they can provide for this typical use for many clients simultaneously. Any Access Point (AP) currently being offered in the UniFi product line offers far greater potential throughput than any client application could realistically require.

If a UniFi Access Point fails to provide the speed that it is capable of, this is most often a result of environmental limitations or other bottlenecks in the deployment. UniFi provides many tools that can help users identify these factors and mitigate them with proper configuration. 

Prerequisites 

The rest of this article assumes that the following prerequisites have been met: 

1. Eliminate any bottlenecks

Before working to improve your Wireless performance, it’s important to identify any bottlenecks outside of your Wireless network. A bottleneck is a point in a network infrastructure that limits performance everywhere else. Often poor Wi-Fi speed is incorrectly assumed to be a result of Wi-Fi hardware/config but actually is the result of a bottleneck upstream from the device. Here are some common examples of bottlenecks: 

• ISP Plan limits performance/speeds far beneath what Wi-Fi is capable of providing. For example, a plan might have a 100Mb/25Mb down/up bandwidth limit on service. Every UniFi device, including legacy devices, is capable of far exceeding this limit. See the image below. 
• Far too few APs for the number of clients/coverage requirements.
• Old/faulty ethernet cables.
• Outdated LAN hardware.
• Outdated Wireless hardware.
• Legacy client devices that don’t support 5GHz.
• Too much noise on a single channel.

The following is an example of a common network bottleneck: 

Diagram illustrating how Wi-Fi speed test results can be limited by ISP 

An easy way to at least rule out any bottleneck is to plug a wired device into the secondary port on an AP and perform the same speed test you are using to test Wi-Fi performance and compare the results to each other. It is normal to see some diminished performance on wireless compared to wired speed tests, but make sure you at least know what your wired network is capable of providing to the AP. 

2. Update your UniFi OS Console and UniFi Access Point (AP) Firmware to Current Version

Ubiquiti’s Firmware updates often include performance improvements: make sure that before testing the performance, you update your UniFi OS Console and your UniFi devices to the most current firmware available.

• UniFi – Set up UniFi Network
• UniFi – Upgrade the firmware of a UniFi device

Common Issues/Steps to Fix

This section examines some of the most common issues that cause diminished speeds on UniFi Networks, as well as the steps that will solve them.

Channel Width

Channel width is the most common cause for poor speed test results after setting up UniFi, especially when being compared to a single wireless router the UniFi devices are replacing. Default UniFi config on 5GHz radio is optimized for large environments (40MHz channel width), while most standalone routers are optimized for use as the only AP in a home/office (80MHz).

To properly test the maximum speed of a UniFi AP, switch to 80 MHz. 80 MHz channels are capable of more than double the peak speed of 40 MHz channels.NOTE: These settings only apply to 5GHz. We do not recommend that channel width be increased from 20 MHz on 2.4GHz as this will often cause worse performance. 

To change AP to use 80MHz channel width, go to Devices > Click on AP to open Properties Panel > Radios > RADIO 5G (11N/A/AC), Change Channel Width from VHT40 to VHT80, click Queue Changes, then Apply Changes. 

Summary: If using a small number of APs, switch 5GHz channel width on APs to 80 MHz for greater peak throughput. In larger environments, note that 40 or 20 MHz channel width is recommended for performance but can limit peak throughput.

Interference/Channel Overlap

The single most potentially negative environmental factor for Wi-Fi performance and stability is wireless interference. Interference can come from external sources like other wireless networks, weather radar, etc. while internal interference can come from devices overlapping with each other on the same channel. 

By default, UniFi Devices are set up with auto channel assignments, but this is something you will want to adjust for your deployment if there are concerns about speed/performance. 

It is recommended that a full site survey be performed for high-density/high-priority Wi-Fi deployments. If that has not been done or the site doesn’t warrant it, the Network application can help you find a better channel assignment for your APs by performing an RF scan. 

To do this, go to Devices > Click on AP to open Properties Panel > Tools > RF Environment and click Scan. User Tips:Running an RF Scan will disconnect any wireless clients currently connected to the AP. Do not run during peak hours if this is a concern. Suggested Channel Settings: 2.4GHz:
Channel width: HT20
Chanel: 1/6/11 Choose one of these channels, an RF scan will help you choose the cleanest one.Transmit Power: Medium5GHz:
Channel width: VHT40 
Optional VHT80/VHT160  (It will increase speeds but might cause more interference.)
Chanel: 36/44 | Optional (149/157) 
Choose one of these channels, an RF scan will help you choose the cleanest one. 
Avoid using DFS Channels unless you understand DFS logic.  (DFS Alerts will cause interruptions) 
Transmit Power: Medium (High)You could also modify your DTIM Periods if you have more modern devices on the network.
Settings > Wireless Network > SSID > 802.11 Rate And Beacon Controls
DITM 2G Period: 3
DITM 5G Period: 3

This scan will take 5-10 minutes and will populate the 2.4GHz channels first and then 5 GHz channels will subsequently be updated.

Once your RF scan is finished, select 5G and you’ll see a list of channels arranged by channel width and how much each channel is being utilized. Select a channel that appears to have the least noise on it and assign your AP to this channel.

To do this go to Devices > Click AP to select it and open Properties Panel > Properties > Radios > RADIO 5G (11N/A/AC), and choose the desired channel. 

If using multiple APs, make sure that each AP does not share the same channel as a nearby AP, and avoid having channels that are adjacent to each other as this can also cause interference. 

Summary: Interference/channel overlap can cause performance to decline. To make sure speed test results are not being impacted by interference, make sure APs are assigned to the optimal channel and not sharing or adjacent to the channel of any nearby APs.

Signal Quality

Another factor that can strongly influence Wi-Fi speed is the signal quality between AP and client device. As clients get further away from an access point and the signal gets weaker, to ensure stability/offer the best possible performance, the AP will lower the rate of the data transfer to compensate. 

When testing peak throughput, be sure to be standing close enough to the AP without obstructions and make sure the client signal strength is close to the maximum of 99%. If your client devices consistently have poor signal strength on 5GHz try increasing Transmit Power on 5GHz. 

To increase TX power on 5GHz, go to device configuration > Radios > Radio 5G (11N/A/AC), and only select “High” from the dropbox under Transmit Power. NOTE: Increasing transmit power on devices can have undesired effects, especially in a very high density environment. Consider starting on High or Auto and only reducing to Medium as needed on a per-AP basis.

Summary: When testing throughput make sure to consider the signal strength between the device and AP, you can find this under the Clients tab in the Network application. If the range on 5GHz is very low, consider increasing Transmit Power on the AP’s 5GHz radio. 

Inconsistent/Inaccurate Speedtest Methods

Another cause for poor speed test performance is inconsistent or inaccurate data. When comparing across devices, make sure to use the same speed test method as different speed test apps can vary wildly. 

While UniFi does include a speed test, the results are often far lower than reality, especially since UniFi’s available speed test servers are limited and results are very sensitive to the proximity of the speed test server. Try using a popular speed test app or website to test to check your UniFi results. Be sure to test multiple times and do not rely on assumptions or past data to inform your comparison.

If you wish to most accurately assess Wi-Fi speed alone and rule out other factors, try performing an iPerf test between a wired and wireless client/between two wireless clients. iPerf only measures bandwidth between two devices on your network. Note that iPerf can still be limited by the syntax you can use, the number of streams, packet size, etc. so make sure you understand what you’re doing before using iPerf. 

Summary: Speedtest results are often inaccurate. Make sure to use consistent speed test methods when comparing between devices, wired vs. wireless, etc. Confirm/test using multiple platforms. UniFi speed tests are often less accurate than other more popular speed test apps. 

Client-specific Issues & Limitations

When benchmarking Wi-Fi, it’s important to also compare across devices to ensure that the client itself isn’t limiting performance. Factors like client CPU utilization, network card driver, Wi-Fi specs, software, all can influence speed test results. 

Make sure to test with multiple devices. To truly measure peak throughput you must test a device that matches the capabilities of the UniFi AP. For instance, if you are testing with a device check the manufacturer specifications to see how many streams the 5GHz antenna supports i.e. Apple iPhone 7 is 2×2, UAP-AC-PRO has 3×3 5GHz radio, thus this iPhone will limit peak throughput. 

If a performance issue with Wi-Fi is isolated to one device, or multiple devices running the same software version, this will almost always point to a problem with the device/software. UniFi doesn’t change how it functions for each variety of client device. Try performing a web search to find other users experiencing similar issues with the same device on other vendor products. 

Keep in mind that declined performance on a single device isn’t a sign of a malfunctioning AP. UniFi APs are backwards compatible with older client devices and the fact that devices are able to connect with their older hardware is a sign the AP is working as designed. 

Summary: Test multiple client devices when benchmarking Wi-Fi performance. Client-specific issues are common but are largely unrelated to AP configuration/hardware.

Additional Steps

After reviewing each of the previous steps, if the issue does not appear to be resolved, check out this article for some further suggestions to troubleshoot wireless performance.

If you’d like to get suggestions from other UniFi administrators, feel free to post on our community.

For issues that point to an issue with UniFi devices/software with respect to wireless performance, feel free to reach out to UniFi support. Please note that the UniFi support team is not able to optimize networks for customers and will not be able to assist with performance issues that are cosmetic in nature or do not indicate an actual UniFi performance issue i.e. improving speed test results from 400 Mbps to 600 Mbps.

Source :
https://help.ui.com/hc/en-us/articles/360012947634-UniFi-Troubleshooting-Slow-Wi-Fi-Speeds-

You can wirelessly adopt access points to your UniFi Network. This allows you to extend your coverage without adding cabling in hard-to-reach areas. When within range of your already-adopted access points, simply connect a new access point to power and it will appear as ready for adoption in the Network application.

• General troubleshooting
• Wireless uplink requirements
• Modifying existing wireless uplink connections
• Frequently Asked Questions

General troubleshooting

Wireless UAP does not appear for adoption

1. Verify that the UAP is powering properly and is ready for adoption (steady white LED).

2. Connect it via Ethernet cable to your network and wait for it to appear for adoption. If it still won’t appear while connected, please see our general adoption troubleshooting steps.

3. Update to the current firmware version if an upgrade is available.

4. Once the UAP is adopted and running the newest version available, disconnect it from the wired LAN, and wait a few minutes while it connects wirelessly. After that, you may disconnect it from power to move it to its final position. Once it powers up again, the UniFi Network application will recognize it and start broadcasting the network’s WiFi through your wireless UAP.

The UAP is adopted but it will not work when moved to wireless networks

1. Verify that the UAP is receiving enough power from the PoE injector. The LED must be a steady blue. Take a look at the UAP’s datasheet to verify power requirements.

2. Verify that the Uplink Connectivity Monitor is enabled within Settings > System Settings > Controller Configuration > Uplink Connectivity Monitor.

3. Verify that there is at least one wired UAP to act as an uplink and that Enable Meshing is turned on within the UAP’s properties panel > RF > Enable Meshing. And that the meshing configuration is set to Auto; or if set to Manual, that Downlink is enabled.

Wireless uplink requirements

• At least one wired access point to serve as the uplink UAP
• A power source (i.e PoE injector) for the wireless UAP (downlink UAP)
• (Recommended) Newest firmware and Network application versions.

Note: The wireless adoption process takes longer than the wired one; expect to wait a little longer for access point detection and for the adoption process to complete.

Modifying existing wireless uplink connections

You can design the topology to your liking by configuring how the wirelessly connected UAPs are linked. To change a UAP’s uplink:

1. Select the UAP from the UniFi Devices section to open its properties panel.
2. Go to the RF tab and select Manual under the Enable Meshing toggle. If the Enable Meshing option is not turned on, do so now to expose the wireless uplink settings.
3. Select which UAP your wireless UAP will connect to (uplink).

Additionally, you can stipulate the uplink priority to define to which uplink your UAP will connect to if there is service degradation or if its current uplink goes offline. Use the Priority dropdown menus to select from the available uplinks.

Frequently Asked Questions

Can a wireless UAP be the uplink to another wireless UAP?

Yes. This is known as a multi-hop wireless uplink and is supported by UniFi, as long as there is one wired access point to provide the first “hop”. Keep in mind that each wireless uplink will suffer service degradation, so this should only be done when necessary.

Can I connect older UAPs wirelessly?

Yes, you just need to make sure to configure them correctly. Some older UAPs only broadcast on a single band (2.4GHz) and will not work the same as newer models. The following older generation UAPs do support wireless uplink on the band they operate on and do not support multi-hop: UAP, UAP-LR, UAP-PRO, UAP-Outdoor, UAP-Outdoor+, UAP-Outdoor5, UAP-IW.

UAP-AC and UAP-AC-Outdoor do not support wireless uplink or multi-hop.

If you have a UAP that does support wireless uplinking and it is still not working, make sure to take the following into account:

	Dual band uplink UAP to dual band downlink UAP: will uplink on 5GHz.
	Dual band uplink UAP to single band downlink UAP: will uplink on the supported frequency of the single band model.
	Single band uplink UAP to single band downlink UAP: will uplink, as long as the same band is supported on both sides of the link.
	Single band (2.4GHz only models) uplink UAP to dual band downlink AP will not be able to uplink.

If you have several wired UAPs, these should have assigned channels that are different and do not overlap with other UAP channels to minimize interference.

• If using all dual band UAPs
  • Set the wired UAP (uplink UAP) to static on 5GHz and to a static on 2.4GHz (1, 6 or 11 making sure it’s not a band also set for any of the other UAPs). Leave the wireless UAP (downlink UAP) set to Auto on the 5GHz radio and set a static channel on 2.4GHz not shared by others.
• If using all single band UAPs
  • Set the wired UAP (uplink UAP) to a static channel on 2.4GHz. Leave the wireless UAP (downlink UAP) set to Auto on 2.4GHz. 
• If using a dual band UAP as the uplink and single band UAP as the downlink
  • Set the wired UAP (uplink) to a static channel on 2.4GHz. Leave the wireless UAP (downlink) set to Auto.
    
    Source :
    https://help.ui.com/hc/en-us/articles/115002262328-UniFi-Network-Troubleshooting-Wireless-Uplinks

With UniFi Network you can forward UDP and TCP ports to an internal LAN device using the Port Forwarding feature on the Dream Machine (UDM and UDM Pro) and USG models.

• Frequently Asked Questions (FAQ)
• Configuring a Port Forwarding Rule
• USG/USG-Pro: Forwarding Ports on WAN2 using Destination NAT
• Troubleshooting Port Forwarding Issues

Requirements

• Applicable to the latest firmware on all UDM and USG models.
• The Port Forwarding feature is designed to only work on WAN1 on the USG models, but it can use both WAN1 and WAN2 on the UDM-Pro.
• It is necessary to manually configure a Destination NAT (DNAT) + WAN firewall rule(s) to forward ports on the WAN2 interface on the USG models, see the section below.

Frequently Asked Questions (FAQ)

Do I need to manually create firewall rules for Port Forwarding?Can I forward ports on the WAN2 interface of the UDM/USG?How does the Port Forwarding feature interact with UPnP?Do I need to manually configure Hairpin NAT?Can I limit which remote devices are allowed to use the forwarded ports? My Port Forwarding rule does not work, what should I do?

Configuring a Port Forwarding Rule

1. Navigate to Settings > Advanced Features > Advanced Gateway Settings and create new port forwarding.

2. Fill in the settings:

• Name: webserver
• Enable Forward Rule: turn this on when ready to activate this rule
• Interface: WAN / WAN2 / Both (UDM Pro only)
• From: Anywhere or Limited
• Port: 443
• Forward IP: 192.168.1.10
• Forward Port: 443
• Protocol: TCP
• Logging: Optional

3. Apply the changes.

Note: On the USG models, it is necessary to manually configure a Destination NAT (DNAT) + WAN firewall rule to forward ports on the WAN2 interface, see the section below.

4. The firewall rule(s) needed for the new Port Forwarding rule you created are automatically added.

5. You can verify the automatically created rules in the Settings > Security > Internet Threat Management > Firewall > Internet section.

USG/USG-Pro: Forwarding Ports on WAN2 using Destination NAT

ATTENTION: This is an advanced configuration that requires creating and modifying the config.gateway.json file. See the UniFi – USG/USG-Pro: Advanced Configuration Using JSON article for more information on using the JSON file.

Follow the steps below to forward ports on the WAN2 interface of the USG models. It is necessary to manually create a Destination NAT (DNAT) rule using the Command Line Interface (CLI) and a custom Firewall Rule using the UniFi Network application. Afterwards, the config.gateway.json file needs to be created or updated to incorporate the custom configuration into UniFi Network.

1. Begin by creating a new custom Firewall Rule within  Settings > Security > Internet Threat Management > Firewall > Internet section.

2. Create a new Firewall Port Group by clicking Create New Group.

3. Fill in the information and specify the port that needs to be allowed through the firewall (443 in this example) and apply changes.

• Name: https
• Type: Port Group
• Port: 443

4. Navigate to    Settings > Security > Internet Threat Management > Firewall > Internet and create new rule.

5. Fill in the information, selecting the previously created Port Group and apply changes.

• General
  • Type: Internet In
  • Description: webserver
  • Enabled: turned on when ready to take this rule live
  • Rule Applied: After (after predefined rules)
  • Action: Accept
  • IPv4 Protocol: TCP
  • Match all protocols except for this: disabled
• Source: Optional
• Destination
  • Destination Type: Address/Port Group
  • IPv4 Address Group: Any
  • Port Group: https (select from any previously created firewall port groups)
• Advanced: Optional

6. The next step is to access the USG using the Command Line Interface (CLI) and add a custom Destination NAT (DNAT) rule. SSH access to your devices must be enabled within    Settings > System Settings > Controller Configuration > Device SSH Authentication.

7. Connect to the USG via SSH.SSH using WindowsSSH using macOS

8. Verify that the WAN2 interface is UP and that it is assigned an IP address by running the following command: 

show interfaces ; sudo ipset list ADDRv4_eth2

Click to copy

unifiadmin@usg:~$ show interfaces 
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address                        S/L  Description                 
---------    ----------                        ---  -----------                 
eth0         203.0.113.1/24                    u/u  WAN                         
eth1         192.168.1.1/24                    u/u  LAN                         
eth2         192.0.2.1/24                      u/u  WAN2                           
lo           127.0.0.1/8                       u/u                              
             ::1/128                          

unifiadmin@usg:~$ sudo ipset list ADDRv4_eth2
Name: ADDRv4_eth2
Type: hash:net
Revision: 3
Header: family inet hashsize 1024 maxelem 65536
Size in memory: 16792
References: 1
Members:
192.0.2.1

NOTE: The ADDRv4_eth2 is a special address group that automatically uses the IP address that is assigned to the eth2 interface. On the USG-Pro, the WAN2 interface uses eth3 instead and thus the address group will be ADDRv4_eth3.

9. Enter configuration mode by typing configure and hitting enter.

10. Add the Destination NAT rule for the WAN2 interface of the USG/USG-Pro (replace eth2 with eth3 for the USG-Pro):

set service nat rule 4001 description 'webserver'
set service nat rule 4001 destination group address-group ADDRv4_eth2
set service nat rule 4001 destination port 443
set service nat rule 4001 inbound-interface eth2
set service nat rule 4001 inside-address address 192.168.1.10
set service nat rule 4001 inside-address port 443
set service nat rule 4001 protocol tcp
set service nat rule 4001 type destination

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11. Commit the changes and exit back to operational mode by typing commit ; exit and hitting enter.

This is an example of the process:

12. Use the mca-ctrl -t dump-cfg command to display the entire config in JSON format:

mca-ctrl -t dump-cfg

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13. The Destination NAT section of the configuration in JSON format can then be used in the config.gateway.json file.

{
       "service": {
                "nat": {
                        "rule": {
                                "4001": {
                                        "description": "webserver",
                                        "destination": {
                                                "group": {
                                                        "address-group": "ADDRv4_eth2"
                                                },
                                                "port": "443"
                                        },
                                        "inbound-interface": "eth2",
                                        "inside-address": {
                                                "address": "192.168.1.10",
                                                "port": "443"
                                        },
                                        "protocol": "tcp",
                                        "type": "destination"
                                }
                        }
                }
       }
}

Click to copy

14. See the UniFi – USG/USG-Pro: Advanced Configuration Using JSON article for more information on how to create and modify the config.gateway.json file.

Troubleshooting Port Forwarding Issues

Refer to the troubleshooting steps below if the Port Forwarding or custom Destination NAT rule is not working. Either of the following options can be the cause:   Possible Cause #1 – The USG/UDM is located behind NAT and does not have a public IP address.   Possible Cause #2 – The UDM/USG is already forwarding the port to another device or has UPnP enabled.   Possible Cause #3 – The traffic from the Internet clients is not reaching the WAN interface of the UDM/USG.  Possible Cause #4 – The LAN host is not allowing the port through the local firewall or does not have the correct route configured. 

Source :
https://help.ui.com/hc/en-us/articles/235723207-UniFi-USG-UDM-Port-Forwarding-Configuration-and-Troubleshooting

Layer 3 adoption is the process of adopting a UniFi device to a remote UniFi Network application.

You might use Layer 3 adoption for applications located in the cloud (e.g. on Amazon EC2) or NOC.

For regular device adoption, see UniFi – Device adoption.

• Overview
• Initial Setup
• Advanced L3 Adoption Methods 
  • DNS
  • DHCP Option 43
  • SSH
• User Notes & Tips

Overview

In many deployments where it’s not possible to have the UniFi Network host running on-premise, you can run the UniFi Network application in the Cloud or your NOC. For example, for a large-scale project with many devices there are a few possible methods for the adoption of devices:

• Take a laptop to the device’s site to perform adoption via Chrome browser (easiest method).
• When you’re at the site, open a browser and navigate to Cloud: either the UniFi Remote Access Portal or the UniFi Network application (when launched using Cloud).
• Create a virtual application instance on Amazon EC2.
• Either configure the DHCP server or DNS server.

Initial setup

Please make sure you’re familiar with how a regular L2 adoption on UniFi works (where the devices and UniFi Network application are on the same network) before attempting L3 (remote) adoption. Also, remember that in order to adopt, the following conditions must be true in order to have internet access and also have access to the router from within the network (locally):

1. WAN port connected to the Internet.
2. LAN port connected locally to access management features on the router (USG or third party).

UniFi APs have a default inform URL http://unifi:8080/inform. Thus, the purpose of using DHCP option 43 or DNS is to allow the AP to know the IP of the UniFi Network application host.

If you encounter discovery issues please use the UniFi – Troubleshooting Device Adoption article to help you troubleshoot the issue.

After installing the Discovery tool plugin (freely available in Chrome Web Store) on a computer running Chrome browser, any locally-available, unmanaged UniFi Devices (i.e., same L2 network as your computer) will appear as “Pending Adoption” in the UniFi Cloud Access Portal as well as your UniFi Network application itself (in the Devices section in both cases). To access the application remotely Remote Access will have to be enabled.

Via UniFi OS

1. Go to https://unifi.ui.com and login with your Ubiquiti SSO credentials.

2. Navigate to the Devices section.

3. The device to be adopted will appear as ready to be adopted. Click Adopt.

Via the UniFi Remote Access Portal

1. Go to https://network.unifi.ui.com/ and log in with your Ubiquiti SSO credentials.

2. Go to the Devices section and locate the model with the Pending Adoption status. Click ADOPT.

3. In the Adopt window that will appear, select the UniFi Network host and the site that will be adopting the device (for multi-site hosts) and click Adopt.

Via the UniFi Network application

1. Launch UniFi Network, go to the Devices section, find the device that is to be adopted with the status “Pending Adoption” and click Adopt under Actions.

DNS

You’ll need to configure your DNS server to resolve ‘unifi’ to your UniFi Network host’s IP address. Make sure that the device can resolve the UniFi Network domain name. For example, if you are setting http://XYZ:8080/inform, then ping from the device to determine if XYZ is resolvable/reachable. Or you may also use FQDN for the application inform URL: http://FQDN:8080/inform

Troubleshooting: Device (with static IP) fails to connect to the L3 UniFi Network application

• When configuring a device from DHCP to static in the UniFi Network application, make sure you have put the IP of DNS. If not, then the device cannot contact DNS to resolve UniFi Network’s domain name.
• If the device has been reset, make sure that you have “informed” the device twice (using the Discovery Utility) about the UniFi Network application’s location. See steps in the section above.

DHCP Option 43

If using Ubiquiti’s EdgeMAX routers, then DHCP option 43 can be done by just entering the IP address of the UniFi Network host in the “unifi” field on the DHCP-server.NOTE: The UniFi Security Gateway (USG) will not use DHCP option 43 to add the UniFi Network application location when obtaining a DHCP lease on the WAN interface.

To use DHCP option 43 you’ll need to configure your DHCP Server. We provide some third party examples below, but please refer to the manufacturer’s support documentation for up to date instructions. For example:

Linux’s ISC DHCP server: dhcpd.conf

# ...
option space ubnt;
option ubnt.unifi-address code 1 = ip-address;

class "ubnt" {
        match if substring (option vendor-class-identifier, 0, 4) = "ubnt";
        option vendor-class-identifier "ubnt";
        vendor-option-space ubnt;
}

subnet 10.10.10.0 netmask 255.255.255.0 {
        range 10.10.10.100 10.10.10.160;
        option ubnt.unifi-address 201.10.7.31;  ### UniFi Network host IP ###
        option routers 10.10.10.2;
        option broadcast-address 10.10.10.255;
        option domain-name-servers 168.95.1.1, 8.8.8.8;
        # ...
}

Cisco CLI

# assuming your UniFi is at 192.168.3.10
ip dhcp pool <pool name>
network <ip network> <netmask>
default-router <default-router IP address>
dns-server <dns server IP address>
option 43 hex 0104C0A8030A # 192.168.3.10 -> CO A8 03 0A

# Why 0104C0A8030A ?
#
# 01: suboption
# 04: length of the payload (must be 4)
# C0A8030A: 192.168.3.10

Mikrotik CLI

/ip dhcp-server option add code=43 name=unifi value=0x0104C0A8030A
/ip dhcp-server network set 0 dhcp-option=unifi

# Why 0104C0A8030A ?
#
# 01: suboption
# 04: length of the payload (must be 4)
# C0A8030A: 192.168.3.10

User Tip: Find more DHCP Option 43 instructions in the User Notes & Tips section.

SSH

If you can SSH into the device, it’s possible to do L3 adoption via CLI command:

1. Make sure the device is running updated firmware. See this guide: UniFi – Changing the Firmware of a UniFi Device.

2. Make sure the device is in the factory default state. If it’s not, run the following command:

sudo syswrapper.sh restore-default

3. SSH into the device and type the following and hit enter, substituting “ip-of-host” with the IP address of the host of the UniFi Network application:

set-inform http://ip-of-host:8080/inform

4. After issuing the set-inform, the UniFi device will show up for adoption in the Devices section of UniFi Network. Once you click Adopt, the device will appear to go offline or have the status of “Adopting” then proceed to “Provision” and “Connected”.

Source :
https://help.ui.com/hc/en-us/articles/204909754-UniFi-Layer-3-Adoption-for-Remote-UniFi-Network-Applications

This article describes how to generate a backup of the UniFi Network application as well as how to restore it. This article does not cover the Auto Backup feature. You may see this article for more information on that subject: UniFi – How to Configure Auto Backup.

Note: This article is applicable to current UniFi Network application versions. Instructions on backups for older versions can be found at the bottom of this page in the “Method 3: Restoring from the /data Directory” section. As always, we suggest you update to the newest software and firmware available.

• Introduction
• Generate a New Backup
• Restore a Backup
• Change the Inform Address for All Devices in the application

Introduction

The UniFi backup file has an extension of .unifi and contains the settings and the database for the UniFi Network application. The database is not included in a “settings only” backup. The backup also includes the config.properties, system.properties and config.gateway.json advanced configuration files, maps, and any customized files in a site’s portal folder. You can download a backup at any time from the Network application following the steps below.

Generate a New Backup

To generate a new UniFi backup file (.unifi), on your UniFi OS Console:

1. Access and log into your UniFi OS Console at unifi.ui.com or locally via its IP address.
2. Go to System Settings > Advanced and enable the Back up Device toggle if disabled.
3. Click Download to download your backup file. 

You can also use the Backup Scheduler to schedule creating a backup at a certain occurrence and time. 

Restore a Backup

Method 1: Restore in the UniFi Network application

To restore a backup you have previously generated:

1. Access and log into your UniFi OS Console at unifi.ui.com or locally via its IP address.
2. Go to System Settings > Advanced and click the Restore in the “Restore Device” section.
3. Select the necessary settings in the Restore Backup pop-up window:
   1. Select the device on the Device Selection drop-down field which you will restore from a backup.
   2. Confirm that you will restore your device either to the latest backup or select another backup from a list by clicking on the here text button.
   3. Enter your SSO account password and click Restore to begin the restoring process. 

Once you confirm, the backup restoration will begin. This process takes a few minutes. Do not disconnect while the application is working on this. Once the new backup is restored, the application will restart.

Method 2: Restore in the UniFi Startup Wizard

If beginning a new installation, it will be easier to just use the option of restore from a previous backup as soon as the UniFi Startup Wizard launches, and select your .unf file.

Method 3: Restore from the /data Directory

Note: This method is for older Network application versions and is not recommended. For security reasons, we suggest always upgrading to the newest release available. If you still wish to use this method, click on the link below.

Change the Inform Address for All Devices in the Network application

ATTENTION:Use this method with caution. After completing these steps the devices will be setting the inform address to the new IP address or FQDN specified.  

It may be desired to change the IP address or FQDN that the UniFi devices on multiple sites are reporting to after an application restore. This process is typically used when migrating from one functional UniFi OS Console to a new install.

1. Download a backup file from the current UniFi OS Console.
2. Install the Network application on the new UniFi OS Console. 
3. Restore the backup that came from step 1 and let the upload process finish.
4. Log into the new UniFi OS Console. 
5. On the old UniFi OS Console’s Network application, go to Settings > System > Other Configuration and enable the Override Inform Host toggle.
6. Type in the new UniFi OS Console’s Hostname or IP Address field. 
7. Select Apply Changes.

After the changes are applied the old UniFi OS Console will send the configuration to adopted and currently connected devices stating the inform host is now what was input in the Hostname or IP Address field.

If this was performed correctly, the devices should start appearing in the new UniFi OS Console. This should not take longer than 5 minutes but can be longer depending on the number of devices, the physical proximity of the devices, and new UniFi OS Console’s technical specification.

Source :
https://help.ui.com/hc/en-us/articles/204952144-UniFi-How-to-Create-and-Restore-a-Backup