Netopia R5100 User Reference Manual page 215

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 R5000 Series Router. 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 R5000 Series Router is 01100000, and the source IP
address after the logical AND is 1011000, this rule does not match and this packet will be forwarded.
Filter Rule:
Incoming packet has the source address of 200.1.1.104.
IP Address
200.1.1.104
AND
255.255.255.240
200.1.1.96
255.255.255.240
Forward = No
Binary Representation
10111000
11110000
10110000
200.1.1.96
255.255.255.240
Forward = No
Binary Representation
01101000
11110000
01100000
(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)
Security 13-37