Netopia D3232 User Reference Manual page 76

8-76 User's Reference Guide
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 D-Series. This rule will forward this packet because the
packet does not match.
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 D-Series's filter rule is 01100000 (=96 decimal), and the
source IP address after the logical AND is 1011000, this rule does not match and this packet will be passed.
Filter Rule:
Incoming packet has the source address of 200.1.1.104.
IP Address
200.1.1.104
AND
10000000
10000000
200.1.1.96
255.255.255.240
Forward = No
Binary Representation of
last byte
10111000
11110000
10110000
200.1.1.96
255.255.255.240
Forward = No
Binary Representation
01101000
(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)
(Source IP Network Address)
(Source IP Mask)
(What happens on match)
(Source address in incoming IP packet)