Security
Firewall
Enable DoS (Denial of Service) Firewall
Threshold: High (WAN bandwidth > 2 Mbps)
  Medium (WAN bandwidth 1 - 2 Mbps)
  Low (WAN bandwidth < 1 Mbps)
If Enabled (recommended), invalid packets and connections are dropped.
The "Threshold" affects invalid connections only.
Options
  Respond to ICMP (ping) on WAN interface
  Allow IPsec
  Allow PPTP
  Allow L2TP