Netopia R2020 User Reference Manual page 238

14-34 User's Reference Guide
Example 2
Filter Rule:
Incoming packet has the source address of 200.1.1.184
IP Address
200.1.1.184
AND
255.255.255.128
This incoming IP packet (10000000) has a source IP address that does not match the network address in the
Source IP Address field (00000000) in the Netopia R2020. This rule WILL forward this packet because the
packet does not match.
Example 3
Filter Rule:
Incoming packet has the source address of 200.1.1.184
IP Address
200.1.1.184
AND
255.255.255.240
Since the Source IP Network Address in the Netopia R2020 is 01100000, and the source IP address after the
logical AND is 1011000, this rule does NOT match and this packet will be passed.
200.1.1.0
255.255.255.128
Forward = No
Binary Representation
10111000
10000000
10000000
200.1.1.96
255.255.255.240
Forward = No
Binary Representation
10111000
11110000
10110000
(Source IP Network Address)
(Source IP Mask)
(What happens on match)
(Source address in incoming IP packet)
(Perform the logical AND)
(Logical AND result)
(Source IP Network Address)
(Source IP Mask)
(What happens on match)
(Source address in incoming IP packet)
(Perform the logical AND)
(Logical AND result)