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Firewall Security
Level Services
This appendix concerns the Firewall options (High, Medium, and Low) section
in the “Configuring Advanced Settings” chapter (see page 43). If one of the firewall
security levels is chosen in the “Firewall Security Level” screen, a table featuring a
list of Internet services and their respective ports appears, along with two configu-
rable columns: “In” signifies whether a particular service can be accessed by a user
outside of the network; and “Out” details whether a computer on the Modem’s
network can access a particular incoming service. The user can select one of the
basic level options, or can manually configure each service by activating and/or
deactivating in and out access.
For example, if “High” is selected in the “Firewall Security Level” screen (as shown
above), the http service uses port 80. Since the check box in the “In” column is
empty, a user outside the Modem’s network cannot access a computer on the net-
work via the http service; in this case, no computers on the network can be used as
a Web server (i.e., to host a Web site accessible to outside users). However, since the
check box in the “Out” column is checked, all computers on the Modem’s network
can access the Internet via the http port.