User guide

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Link: Packet Filter
When you click Packet Filter , the Filter Sets screen appears.
Security should be a high priority for anyone administering a network connected to the
Internet. Using packet filters to control network communications can greatly improve your
network’s security. The Packet Filter engine allows creation of a maximum of eight Filter
Sets. Each Filter Set can consist of many rules. There can be a maximum of 32 filter rules
in the system.
☛ WARNING:
Before attempting to configure filters and filter sets, please read and under-
stand this entire section thoroughly. Netopia Gateways incorporating NAT have
advanced security features built in. Improperly adding filters and filter sets
increases the possibility of loss of communication with the Gateway and the
Internet. Never attempt to configure filters unless you are local to the Gate-
way.
Although using filter sets can enhance network security, there are disadvan-
tages:
• Filters are complex. Combining them in filter sets introduces subtle interac-
tions, increasing the likelihood of implementation errors.
• Enabling a large number of filters can have a negative impact on perfor-
mance. Processing of packets will take longer if they have to go through many
checkpoints in addition to NAT.
• Too much reliance on packet filters can cause too little reliance on other
security methods. Filter sets are not a substitute for password protection,
effective safeguarding of passwords, and general awareness of how your net-
work may be vulnerable.