Hello,

to allow specific devices to access internet, you can use access control to satisfy your needs. Below is the instruction:

https://www.tp-link.com/en/faq-1067.html 

Note: The device under whitelist can access internet, while the device cannot access internet in blacklist mode.

The devices in the same network can access each other, it cannot be blocked, while there is a workaround, you can enable guest network, and do NOT enable "Allow Guests To Access My Local Network", and then the devices connected to the guest network cannot access the host network. 

Regarding to the server, may I know what it is? If it is a computer or something which connects to the router by wired cable/wifi, then the devices in the same network can access it, while if it is some kind of hard drive disk, you may enable USB sharing function to meet your needs. 

https://www.tp-link.com/en/faq-756.html

May it help.

Good day. 

Clifton wrote

...
I need a way to block access to the internet, but still allow people to access the LAN and my server.  I also can't tell who will be attempting to login, so I can't just put devices in the Blacklist or Whitelist unless I am monitoring the network when they login.  Since I'm not in my room all the time, that is an impossible task

....

 

Hi, to block access to internet but still allow them to access each other in the same network, it is suggested to setup parental control.

Below is the instruction: https://www.tp-link.com/en/faq-1124.html

Note: You can add the device into whitelist without any keywords, and choose all days as internet access time, then these devices cannot access internet while can access each other.

For C8, to block access to the internet by using a range of IP address is the same thing as we did on the C9; actually, it is much easier to do that in C9. 

You can use parental control to give it a go.

Good day.