Asus RT-AC66U - Manual (Page 82)

4.6.4 Network Services Filter
The Network Services Filter blocks LAN to WAN packet exchanges
and restricts network clients from accessing specific web services
such as Telnet or FTP.
To set up a Network Service filter:
1. From the navigation panel, go to Advanced Settings >
Firewall > Network Service Filter tab.
2. On the Enable Network Services Filter field, select Yes.
3. Select the Filter table type. Black List blocks the specified
network services. White List limits access to only the specified
network services.
4. Specify the day and time when the filters will be active.
5. To specify a Network Service to filter, enter the Source IP,
Destination IP, Port Range, and Protocol. Click the button.
6. Click Apply.