Eicon Networks DIVA LAN ISDN - Manual (Page 128)

Chapter Nine: Advanced Installations IP filters 128
IP filters
IP filtering provides you with the means to implement customized security, usage, and cost control measures.
How filtering works
Filters are defined in a stack. Up to 8 filters can be combined together to obtain sophisticated results. Data
cascades through the filter stack as follows:
Each profile has its own filter stack. However, note that once any filter is activated, all incoming and
outgoing data passes through the filter stack. By default, the DIVA LAN ISDN Modem defines three filters.
This means, unless you turn these filters off, all incoming and outgoing data passes through the filter stack.
Note More sophisticated filters can be defined using the command line interface. See Chapter Ten for more
information.
Filter #2
Filter #1
Data that matches
Data that matches
Drop
Drop
Forward
Forward
Apply filter
conditions
Apply filter
conditions
Action
Action
Data that does
not match
Data that does
not match
Filter #8
Output from filter stack
Input to filter stack
Data that matches
Drop
Forward Apply filter
conditions
Action
Data that does
not match
No
Yes
Are any filters
active?
Bypass filter stack
Send all data into filter stack
Discard
Discard
Discard
Discard