Netopia R2020 User Reference Manual page 239

Example 4
Filter Rule:
Incoming packet has the source address of 200.1.1.104
IP Address
200.1.1.104
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 01100000, this rule DOES match and this packet will NOT be passed.
Example 5
Filter Rule:
Incoming packet has the source address of 200.1.1.96
IP Address
200.1.1.96
AND
255.255.255.255
Since the Source IP Network Address in the Netopia R2020 is 01100000, and the source IP address after the
logical AND is 01100000, this rule DOES match and this packet will NOT be passed. This rule masks off a
SINGLE IP address.
200.1.1.96
255.255.255.240
Forward = No
Binary Representation
01101000
11110000
01100000
200.1.1.96
255.255.255.255
Forward = No
Binary Representation
01100000
11111111
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 14-35