Netopia D3100-I IDSL, D3232 IDSL, D7100 SDSL, D7171 SDSL - page 76

8-76 User’s Reference Guide
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.
EE
EExx xxaa aamm mmpp pp llll ee ee 33 33
Incoming packet has the source address of 200.1.1.184.
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.
EE
EExx xxaa aamm mmpp pp llll ee ee 44 44
Incoming packet has the source address of 200.1.1.104.
255.255.255.128 10000000 (Perform the logical AND)
10000000 (Logical AND result)
Filter Rule: 200.1.1.96 (Source IP Network Address)
255.255.255.240 (Source IP Mask)
Forward = No (What happens on match)
IP Address Binary Representation of
last byte
200.1.1.184 10111000 (Source address in incoming IP packet)
AND
255.255.255.240 11110000 (Perform the logical AND)
10110000 (Logical AND result)
Filter Rule: 200.1.1.96 (Source IP Network Address)
255.255.255.240 (Source IP Mask)
Forward = No (What happens on match)
IP Address Binary Representation
200.1.1.104 01101000 (Source address in incoming IP packet)
AND