I have some problems here, I am trying to stop sharing on mikrotik, but I can find nothing, is there anyone that can help me out on this, I am using authentication server through IP address.
se vede ca esti roman.
Use pppoe.
Use Firewall rules to stop it and disable default forwarding.
Max
http://mikrotikexpert.com
http://maxid.com.ar
this is working only with wireless clients.
Default forwarding is for wireless
firewall rules for IP (layer 3)
Maxi
http://mikrotikexpert.com
http://maxid.com.ar
yes but not work 
I suppose you have misconfigured firewall rules or clients that can communicate to each other are connected to switch. If this is a switch case then router can’t block it