Unifi Guest Wifi Unable To Obtain IP Address

Having trouble getting your guest WiFi portal working using UniFi?

I did too and its most likely caused by you using a separate DHCP server on the network rather than using your USG for DHCP.

Here is the fix!

Go into ‘Wireless Networks’ and Edit the guest WiFi network.


Scroll down to ‘Advanced Options’ and you will see an are to enter Excepted Devices. These devices are allowed to receive broadcast traffic over the internet which includes DHCP requests and responses. The default entry here includes your USG gateway by default but if you’re not using it as a DHCP server you need to add an entry here.

Click on ‘Add Clients’



Next select the MAC address of the DHCP server on your network. In my test lab I am using a Windows 2016 Server as my DHCP server. Tick the MAC address and click on Apply.



Click ‘Save’ to provision the changes and after a minute or two devices on the guest network will be able to talk to the USG and your DHCP server.



Below shows my mobile phone registering on the network over the guest network.




Now you may be wondering what happens if your DHCP server is also a file server on the network. Will adding an exception for the DHCP server mean that guest devices will now be able to speak to the server?

NO! Guest devices will not be able to connect to any folder shares or even ping the server IP address.


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Author: Ian@SlashAdmin

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  1. Thanks for a very good detailed tutorial which solved my problem.

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  2. Finally.. the answer I was looking for, for some reason official documentation doesnt cover this. You would think most ‘enterprises’ would use their own DHCP server.

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    • Happy to help!

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  3. Thanks Ian. Your description of the problem and solution were spot on. We just moved to UNIFY and was not expecting GUEST network to not work.

    Unify should fix this issue because most organisations use DHCP servers internally. Cheers.

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    • You’ve not understood what you’ve just done have you. This is not a bug for unifi to fix, it is the default and correct behaviour

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      • Yes this is not a bug and never said it was! But if you want dhcp on your guest WiFi to work this is one way to do it. Feel free to share another so we all benefit from other options.

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  4. Thanks. It worked perfectly. It seems because our DC are sitting on a Load Balancing Hosts, the MAC Addresses actually change depending on where the server is sitting. So its best to put all MAC addresses of the Hosts in the list.

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  5. Thanks, i have it working at last.
    In my situation the mac address of my dhcp router was not listed in the ‘+ Add Clients’ box, so I looked it up in portal of my dhcp router, and manually typed that MAC address over in the box in ‘Excepted Devices’ and clicked ‘+ Add’, (it was accepted), and Save.
    After successful provisioning AC point, my guest network internet is working.

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  6. Under advanced options UN-CHECK “Block LAN to WLAN Multicast and Broadcast Data”

    Solved my issue.

    Post a Reply

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