Netopia R910 Manuale Utente

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Discarded if all the filters are configured to pass (for ward)

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Discarded if the set contains a combination of pass and discard filters

Although using filter sets can greatly enhance network security, there are disadvantages:

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Filters are complex. Combining them in filter sets introduces subtle interactions, increasing the likelihood 
of implementation errors.

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Enabling a large number of filters can have a negative impact on per formance. Processing of packets will 
take longer if they have to go through many checkpoints.

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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, caller ID, the “must match” 
option in the answer profile, PAP or CHAP in connection profiles, callback, and general awareness of how 
your network may be vulnerable. 

The ultimate goal of network security is to prevent unauthorized access to the network without compromising 
authorized access. Using filter sets is par t of reaching that goal. 

Each filter set you design will be based on one of the following approaches:

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That which is not expressly prohibited is permitted.

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That which is not expressly permitted is prohibited.

It is strongly recommended that you take the latter, and safer, approach to all of your filter set designs.

To work with filters and filter sets, begin by accessing the filter set screens.

Note: Make sure you understand how filters work before attempting to use them. Read the section 

Main

Menu

System

Configuration

Filter

Sets

IP Filter Sets