IP address not listed in devices in hub

[#1]

Hope someone can help- I want to schedule access for my son's PC. Initially found his IP address listed and set a schedule but needed to change the schedule so deleted it in order to create a new one. Now his IP is not showing on the device list. I can see his activity on the technical log. I’ve restarted the router and checked the WiFi settings are not private for him or changed. Any advice on how to get his device showing on the list again so I can set up access?
Thanks

[#2]

Some Hubs / Routers do not show a device if it has an IP outside the DHCP range,
E.g . there is a static IP set on the PC or perhaps a Reserved IP. 

Given all mobiles and computers now have MAC Address Randomisation,
using MAC Filter List can be a very ineffective way of blocking access.

[#3]

Thanks for your reply- but if it was picked up fine at first and now doesn’t appear without any settings being changed, it’s still a mystery… unless u have any other ideas? And I see the IP in the technical log. So why would it not be visible in the device list?

[#4]

Is the IP in the DHCP allocation range ?

Is the MAC Address changing over time ?

[#5]

Looking now I can see the MAC address has changed… how can I check if it is in DHCP range?

[#6]

@Bgu2026 

Any IP address from 192.168.1.64 and 192.168.1.253 will be allocated by the Hub.

Everytime the device MAC address changes it will be allocated a different IP.

[#7]

Thanks for your help. I’m obviously way out of my depth here..! If I check the system settings on the PC, the Mac address should reflect the changed address? Because the IP is the same… I’ll have another look at everything and come back here.
Thanks again

[#8]

@Bgu2026 

Just an note, if the PC is connected using wired (LAN port) rather than WiFi then the MAC address should stay the same as MAC address randomising is for WiFi only, it is an extra layer of security when roaming using public Wifi systems.