Smart hub 2 - Ethernet ports / DHCP

[refugeefromplusnet]

I've been using a smart hub 2 for one month and devices (star micronics printers) that are connected directly to the ethernet ports were working for a few weeks but have now stopped working. Specifically they are not being served IP addresses via DHCP. 

The same printers and cables work when plugged into other ethernet routers. 

What could  be going on and how to fix??? 

[rbz5416]

There is apparently a bug in BT routers whereby expired DHCP leases aren't returned to the pool,so the server runs out of addresses. Try a factory reset but if you have Digital Voice, back up your contacts first.

To minimise the effect, disable MAC randomisation from any devices using it, typically mobile devices & laptops/Pcs.

[refugeefromplusnet]

Thanks. I guess that increasing the expiry period from 1 day to 21 will also help.

What's the issue with contacts? Are they stored in the router? 

[rbz5416]

No idea about thee lease time as I don't use BT routers, but it can't hurt to try. But It's only going to delay the inevitable. With MAC randomisation on, a device will acquire a different address every time it connects.

Yes, if you use BT's DV handsets, the contacts are stored on the router.

[WSH]

Your best bet with something like a printer is to give it a static address.

[refugeefromplusnet]

Update - I've been using a smart hub 3 for one month and devices (star micronics printers) that are connected directly to the ethernet ports were working for a few weeks but have now stopped working. Specifically they are not being served IP addresses via DHCP. 

The same printers and cables work when plugged into power line devices which are connected to the same hub (obvs the powerline is serving the DHCP).  

I have factory reset (from the admin page AND from the button on the rear) and these devices are not recognised.   

What else can I do? Replacement router?

[rbz5416]

Are you certain that the Hub actually reset? They can can 20-30s of the button being held in before they reset. If so then as suggested by @WSH on your original thread, try setting static IP addresses for the printers.

https://community.bt.com/t5/Home-setup-Wi-Fi-network/Smart-hub-2-Ethernet-ports-DHCP/m-p/2385850

Starting a second thread for the same subject really isn't helpful.

[licquorice]

@refugeefromplusnet  I have merged your posts. Creating more than one thread for the same problem just causes total confusion and duplicated answers.

[refugeefromplusnet]

40 Seconds to reboot the SmartHub3  - wait for the flash, but DHCP never restarted for these printer(s).

Advise taken, many thanks. Attached printers to another network, set static IP and then reconnected to the SmartHub3. Plus set the other devices on the ethernet ports of the SmartHub3 to not change IP addresses.

A thoroughly painful experience. And of course I had already bought a new printer because after I had checked the cable with the original printer then what else could be going on?