Motorola Netopia 3342N - Manual (Page 154)

Administrator’s Handbook
154
Link: Stateful Inspection
All computer operating systems are vulnerable to attack from outside sources, typically at the operating
system or Internet Protocol (IP) layers. Stateful Inspection firewalls intercept and analyze incoming data
packets to determine whether they should be admitted to your private LAN, based on multiple criteria, or
blocked. Stateful inspection improves security by tracking data packets over a period of time, examining
incoming and outgoing packets. Outgoing packets that request specific types of incoming packets are
tracked; only those incoming packets constituting a proper response are allowed through the firewall.
Stateful inspection is a security feature that prevents unsolicited inbound access when NAT is disabled. You
can configure UDP and TCP “no-activity” periods that will also apply to NAT time-outs if stateful inspection is
enabled on the inter face. Stateful Inspection parameters are active on a WAN inter face only if enabled on
your Gateway. Stateful inspection can be enabled on a WAN inter face whether NAT is enabled or not.
Stateful Inspection Firewall installation procedure
☛
NOTE:
Installing Stateful Inspection Firewall is mandator y to comply with Required Ser vices Security
Policy - Residential Categor y module - Version 4.1 (specified by ICSA Labs)
For more information please go to the following URL:
http://www.icsalabs.com/icsa/docs/html/communities/firewalls/pdf/4.1/baseline.pdf
1. Access the router through the web interface from the private LAN.
DHCP ser ver is enabled on the LAN by default.
2. The Gateway’s Stateful Inspection feature must be enabled in order to prevent TCP,
UDP and ICMP packets destined for the router or the private hosts.
This can be done by navigating to Expert Mode -> Security -> Stateful Inspection.
• UDP no-activity time-out: The time in seconds after which a UDP session will be terminated, if there is
no traffic on the session.
• TCP no-activity time-out: The time in seconds after which an TCP session will be terminated, if there
is no traffic on the session.