Netopia R2121 User Reference Manual page 197

This incoming IP packet has a source IP address that matches the network address in the Source IP Address
field (00000000) in the Netopia R2121. This will NOT forward this packet.
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 R2121. 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
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)
Security 14-35