firewall built into Fedora Core checks every
incoming and outgoing network connection on your machine against a
set of rules. These rules specify which types of connections are
permitted and which are denied.
By default the firewall is enabled, with a simple set of rules
that allow connections to be made from your system to others, but
permit only network browsing and
SSH (Secure SHell) connections from other systems. You may make
changes on this screen to allow access to specific network
services on your Fedora system.
Figure 18.3. Firewall Screen
To enable access to the services listed on this screen, click the
check box next to the service name.
||SSH Provides Immediate Remote Access
All Fedora systems automatically run the SSH remote access
service, and the default firewall configuration allows
connections to this service. The default configuration ensures
that administrators have immediate remote access to new systems
through the user and
To enable access to other services, select
the details. Use
field to specify either the port
number, or the registered name of the service. Select the relevant
from the drop-down. The majority of
services use the TCP protocol.
||The Services List
/etc/services file lists service port
numbers and names that are registered with the Internet Assigned
Names Authority (IANA).
If a service uses more than one port number, enter each port. For
example, an IMAP service enables users to access their e-mail from
another system through TCP port 143. To permit IMAP connections
to your system, add
or port number
Avoid disabling the firewall. If you believe that it is necessary
to do so, select
||Changing the Firewall Settings
To change these settings later, choose