I'm using Debian for a small LAN server, dividing an ADSL connection, i made htb scripts for hard download/upload rate ofr my users. but...

some of them use multiply IP's to get unrestricted
access to the network.

i want to have scripts running which could limit the access to the internet only to those people using specific IP's ... is it possible ? if it is - how ??

i found some static-arp scripts, but they just block specific MAC adresses. i don't want to block MAC's i want to block all IP's besides those which i choose for my LAN users

thx for the help...

best regards