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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.