Netopia 2200 Manual Do Utilizador

Página de 351
 
154
 
Link: 
Packet Filter
 
When you click the 
 
Packet Filter
 
 link 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 per for-
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.
Netopia Firmware Version 7.6’s packet filters are designed to provide security for the Inter-
net connections made to and from your network. You can customize the Gateway’s filter 
sets for a variety of packet filtering applications. Typically, you use filters to selectively