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4.6.1 Packet Filter
Packet Filter enables you to control what packets are allowed to pass the router. Outbound filter applies
on all outbound packets. However, Inbound filter applies on packets that destined to Virtual Servers or
DMZ host only. You can select one of the two filtering policies:
1.
Allow all to pass except those match the specified rules
2.
Deny all to pass except those match the specified rules
You can specify 8 rules for each direction: inbound or outbound. For each rule, you can define the
following:
•
Source IP address
•
Source port address
•
Destination IP address
•
Destination port address
•
Protocol: TCP or UDP or both.
•
Use Rule#
For source or destination IP address, you can define a single IP address (4.3.2.1) or a range of IP
addresses (4.3.2.1-4.3.2.254). An empty implies all IP addresses.
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For source or destination port, you can define a single port (80) or a range of ports (1000-1999). Add
prefix "T" or "U" to specify TCP or UDP protocol. For example, T80, U53, U2000-2999. No prefix
indicates both TCP and UDP are defined. An empty implies all port addresses.
Packet Filter
can work
with
Scheduling Rules
, and give user more flexibility on Access control. For Detail, please refer to
Scheduling Rule
.
Each rule can be enabled or disabled individually.
Inbound Filter:
To enable
Inbound Packet Filter
click the check box next to
Enable
in the
Inbound Packet Filter
field.
Suppose you have SMTP Server (25), POP Server (110), Web Server (80), FTP Server (21), and News
Server (119) defined in Virtual Server or DMZ Host.
Example 1:
(1.2.3.100-1.2.3.149) They are allow to send mail (port 25), receive mail (port 110), and browse the
Internet (port 80)
(1.2.3.10-1.2.3.20) They can do everything (block nothing)
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Others are all blocked.
Example 2:
(1.2.3.100-1.2.3.119) They can do everything except read net news (port 119) and transfer files via FTP
(port 21)
Others are all allowed.
After
Inbound Packet Filter
setting is configured, click the
save
button.
Outbound Filter:
To enable
Outbound Packet Filter
click the check box next to
Enable
in the
Outbound Packet
Filter
field.
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Example 1:
(192.168.123.100-192.168.123.149) They are allowed to send mail (port 25), receive mail (port 110),
and browse Internet (port 80); port 53 (DNS) is necessary to resolve the domain name.
(192.168.123.10-192.168.123.20) They can do everything (block nothing)
Others are all blocked.
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Example 2:
(192.168.123.100-192.168.123.119) They can do everything except read net news (port 119) and
transfer files via FTP (port 21)
Others are allowed
After
Outbound Packet Filter
setting is configured, click the
save
button.
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