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Service
In this section, network services are defined and new network services can be
added. There are three sub menus under Service which are: Pre-defined,
Custom, and Group. The Administrator can simply follow the instructions below
to define the protocols and port numbers for network communication
applications. Users then can connect to servers and other computers through
these available network services.
What is Service?
TCP and UDP protocols support varieties of services, and each service consists
of a TCP Port or UDP port number, such as TELNET(23), SMTP(25),
POP3(110),etc. The DFL-80 Firewall defines two services: pre-defined service
and custom service. The common-use services like TCP and UDP are defined
in the pre-defined service and cannot be modified or removed. In the custom
menu, users can define other TCP port and UDP port numbers that are not in
the pre-defined menu according to their needs. When defining custom services,
the client port ranges from 1024 to 65535 and the server port ranges from 0 to
1023.
How do I use Service?
The Administrator can add new service group names in the
Group
option under
Service
menu, and assign desired services into that new group. Using service
group the Administrator can simplify the processes of setting up control policies.
For example, there are 10 different computers that want to access 5 different
services on a server, such as HTTP, FTP, SMTP, POP3, and TELNET. Without
the help of service groups, the Administrator needs to set up 50 (10x5) control
policies, but by applying all 5 services to a single group name in the
service
field, it takes only one control policy to achieve the same effect as the 50 control
policies.