On this page, you can configure WAN-to-LAN filtering to prohibit certain IP addresses in the WAN from accessing the LAN.
Enable IP Filter:
Filter Mode:
  Protocol LAN-side IP Address LAN-side Port WAN-side IP Address WAN-side Port
Configure
Protocol:
LAN-side IP Address: ---
LAN-side Port: ALL
User-defined
  Specific: 
  Range:    ---
WAN-side IP Address: ALL
User-defined
---
WAN-side Port: ALL
  User-defined
  Specific:
  Range: ---