BT Home Hub 5 (Type B) | Software version v0.07.06.01239-BT
Recently my HH5b has started to forget DHCP saved names and address asignments. This is particularly annoying for devices I have applied both names and static IP's to. I have about 30 or so devices (TV's NAS, cameras, phones, ipads etc) which were all sensibly named but everytime the hub reboots then I seem to lose the majority of names and they are shown as the Mac address or similar in the home netweork menu and in most cases are no longer accessible by the name eg "NAS" that I have given them.
the DHCP table used to contain all the entries but now only contains 10.
Why doesn't the hub remember the details any more ?
It has worked fine for a few years, maybe it's just been tipped over the edge although it's possible the last firmware update trolled it.
A factory reset is the only way to clear the DHCP table, its a known issue with all of the BT Home hubs.
If you can, then manually set the IP address on the device itself, outside of the DHCP range of the home hub.
This is usually easy with TVs, NAS and IP cameras, but other mobile stuff will have to rely on DHCP.
Another option is to turn off DHCP on the home hub, and use a different device to service DHCP requests. I use a TP-Link wireless access point to do that.
As @Liam_ has suggested, a proper router that support DHCP address reservation, is a better option.