3Com 812 Use of a forged IP source address to circumvent a firewall, Discards it, Capabilities

6-26CHAPTER 6: MANUAL SETUP

Packet filters control inter-network data transmission by accepting or rejecting the passage of specific packets through network interfaces based on packet header information. When data packets are received by a network interface such as an Ethernet (LAN) or WAN port, a packet filter analyzes the packet information using a set of rules you define. A filter then lets the packet pass through or discards it.

This chapter contains information on the filtering capabilities for your

OfficeConnect Remote 812. It is divided into the following sections:

Filtering Overview

OfficeConnect Remote 812 Filtering Capabilities

Creating Filters

Assigning Filters

Applying Filters

	￿Managing Filters
Filtering Overview	Filters can provide added security by accepting packets only from specific
	addresses or they can be added to reduce network traffic and improve overall
	performance. Filters can also be used to approximate spoofing when routers with
	different or incompatible spoofing methods are linked over the WAN. Spoofing is
	the use of a forged IP source address to circumvent a firewall.
	Packet filters control inter-network data transmission by accepting or rejecting the
	passage of specific packets through network interfaces based on packet header
	information. When data packets are received by a network interface such as an
	Ethernet LAN or WAN port, a packet filter analyzes packet header information
	against a set of rules you define. A filter then lets the packet pass through or
	discards it.
OfficeConnect Remote	The OfficeConnect Remote 812 provides an extensive set of data and call filtering
812 Filtering	capabilities. The OfficeConnect Remote 812 supports the following filtering
Capabilities	capabilities:
	Input and output data filtering.
	Source and destination address filtering.
	Protocol filtering.
	Source and destination port filtering. A packet filter can control what services
	local or remote users can access.
	Call filtering can control whether a packet can initiate an outgoing call.

Route filtering can filter source and destination addresses in packets that

￿exchange routing table information.

Established session filtering. A packet filter can permit users to connect with a remote network without letting remote users have access to the local network (or vice versa).

Filter Classes The OfficeConnect Remote 812 supports three filter classes: