Quick Reference Guide

ProSafe VPN Firewall 50 FVS338 Reference Manual
4-16 Firewall Protection and Content Filtering
v1.0, January 2010
3. Check the boxes for the attack checks that you wish to monitor. The various types of attack
checks are listed and defined below.
4. Click Apply to save your settings.
The various types of attack checks listed on the Attack Checks screen are:
• WAN Security Checks
– Respond To Ping On Internet Ports. By default, the VPN firewall responds to an ICMP
Echo (ping) packet coming from the Internet or WAN side. Responding to a ping can be a
useful diagnostic tool when there are connectivity problems. If the ping option is enabled,
you can allow either any IP address or a specific IP address only to respond to a ping. You
can disable the ping option to prevent hackers from easily discovering the VPN firewall
via a ping.
– Enable Stealth Mode. If stealth mode, the VPN firewall will not respond to port scans
from the WAN, thus making it less susceptible to discovery and attacks.
– Block TCP Flood. A SYN flood is a form of denial of service attack in which an attacker
sends a succession of SYN requests to a target system. When the system responds, the
attacker does not complete the connections, thus leaving the connection half-open and
flooding the server with SYN messages. No legitimate connections can then be made.
Figure 4-9