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IPV4 DHCP failure BusinessHUB


Hi there

Business customer here. 

Had an interesting fault develop. I think the businesshub has become corrupted. (Tried factory reset but oroblem persits). I think I need a new hub sent out. We had a flickering type power fault in our area. 

Problems details follow:

When connecting wirelessly or wired to the hub the DHCP  addresses are only set correctly for IPV6. IPV4 addresses get allocated to windows (and android) as etc... 

However the default for the hub is 

I can connect wirelessly but due to the ip mismatch but for everything that requires ipv4 nothing is routed correctly . If I statically change the ip address on a laptop to and set the default gateway to DNS to (or  Everything works. 

Interestingly the All of the hubs settings have remained the same. But as of this afternoon only IPV6 addresses get correct settings from the DHCP. So only sites using IPV6 are accessible. 

The IP address of the hub is still the subnet mask is still

The DHCP range is still - (Default)

But the IPV4 addresses received by the connecting machines are all in the range - 120 or so. 

Is this common? A hardware faut?  Or perhaps a firmware update that has a bug?

Though the firmware hasn't updated that recently....

BT Business Hub 5 (Type A) | Software version | Last updated 20/11/19



As a workaround I am going to try and get all ipv4 stuff I need to work setup with static addresses. (Or I might be able to set up an independent dhcp server if I can find a spare box or the time).... 

I have held the firmware reset button in for fifteen seconds or so as advised that this might sort it out (when turning off and on again did not work)....

The same problem persists.  So think there is something more severe happening Perhaps the box is on it's way out. 

How would I go about getting a replacement?

I'll try the business helpline in the morning in between Zoom Classes and nursery runs and work e-mails.

And update if anyone has simlair issues....

Thanks in advance if anyone know of a simple fix. 

All the best



After a frustracting call with support. 

I am back where I started. 


The support did not seem to understand the difference between the LAN and the WAN of the BT Hub

insisted on setting a static IP for the router. 


Unfortunately (unsurprisingly) this has had no effect on the DHCP for the Lan and new devices are still being given the wrong IPV4 addresses. 


A freshly connected phone when accessing




The IP addresses given out by the BusinessHUB are



Which considering the DHCP settings are: 

hub settings.png


is clearly wrong. 

I will try to speak to someone again  and get the HUB replaced as I think this must be a firmaware issue



Ho hum....





After my second call asking for a replacement box I was informaed that they no longer send out replacement boxes for free and I will need to pay £100 and £8.99 for delivery for a new box. 

Pretty surprised by this, as I'm pretty sure my original contract claimed that the HUB was owned by BT.... so I could be charged to replace BT's own hardware.... Maybe I'm wrong. 


So I'm considering getting a new box as a replacement that is better than the BusinessHUB is there any suggestions, and will I need a username and password to get the broadband sorted on the new box. How do I go about getting this password as it is not visible in the BusinessHUB. And I've checked my original documents and it is not listed anywhere....




There is no password...


The userid is


Hope this helps you get connected with another router.




I too have issues with DHCP - I think it is a bug.  I plan to put my Smart Hub in Bridge mode and use a spare wifi router to do my DHCP.


I have just moved from a residential to a business account hoping these issues would go away!  I might even buy a new router to get the latest features.


You need to ask BT Business for your user name and password.  BT Domestic customers don't have unique log ins but business customers do.  Also ask for a static IP as this is included in the price.  I have just setup a Draytek Vigor modem to replace the BTB Smart Hub 6A


Hi hairymarmite,


I’m sorry you are having issues with your Business Smarthub. If these issues persist or you have any other questions regarding your BT Business service. Please PM me and I will help answer your queries.