Broadband VPN Router User’s Manual
70
Options
Respond to ICMP
(ping)
The ICMP protocol is used by the "ping" and "trace route" programs,
and by network monitoring and diagnostic programs.
• If checked, VRT-311 / VRT-311S will respond to ICMP packets
received from the Internet.
• If not checked, ICMP packets from the Internet will be ignored.
Disabling this option provides a slight increase in security.
Allow VPN pass-
through
If enabled, PCs on the LAN can use VPN software to connect to
remote clients via the Internet connection. The protocols supported
are:
• IPSec
IPSec protocol is used to establish a secure connection, and is
widely used by VPN (Virtual Private Networking) programs.
• PPTP
PPTP (Point to Point Tunneling Protocol) is widely used by VPN
(Virtual Private Networking) programs.
• L2TP
L2TP is a protocol developed by Cisco for VPNs (Virtual Private
Networks).
Drop fragmented
IP packets
If enabled, fragmented IP packets are discarded, forcing re-
transmission of these packets. In some situations, this could prevent
successful communication.
Normally, this setting should be disabled.
Block TCP Flood
A TCP flood is excessively large number of TCP connection requests.
This is usually a DoS (Denial of Service) attack.
This setting should normally be enabled.
Block UDP Flood
A UDP flood is excessively large number of UDP packets. This is
usually a DoS (Denial of Service) attack.
This setting should normally be enabled.
Block non-
standard packets
Abnormal packets are often used by hackers and in DoS attacks, but
may also be generated by mis-configured network devices. (PCs will
normally not generate non-standard packets.)
This setting should normally be enabled.