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.
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:
(192.168.9.1-192.168.9.14) They are allow to send mail (port 25), receive mail (port 110), and browse your web server as above. (port 80)
(192.168.9.15-192.168.9.100) They can do everything (block nothing)
Others are all blocked.