Red Hat LINUX 7.1 - PSERIES Manual page 53

Section 4.16:Firewall Configuration
If you are connecting your system to the Internet, but do not plan to run a server, this is the safest
choice. If additional services are needed, you can choose
through the firewall.
Medium
If you choose Medium
resources on your system. By default, access to the following resources are not allowed:
• Ports lower than 1023 — the standard reserved ports, used by most system services, such as
FTP, SSH, telnet, and HTTP
• The NFS server port (2049)
• The local X Window System display for remote X clients
The X Font server port (by default, xfs does not listen on the network, it is disabled in the
•
font server)
If you want to allow resources such as RealAudio™, while still blocking access to normal
system services, choose
the firewall.
No Firewall
No firewall provides complete access to your system and does no security checking. Security
checking is the disabling of access to certain services. It is recommended that this only be
selected if you are running on a trusted network (not the Internet), or if you plan to do more
detailed firewall configuration later.
Choose to add trusted devices or to allow additional incoming services.
Customize
Trusted Devices
Selecting any of the
device; it is excluded from the firewall rules. For example, if you are running a local network,
but are connected to the Internet via a PPP dialup, you can check
from your local network will be allowed. Selecting
Ethernet is allowed, put the ppp0 interface is still firewalled. If you want to restrict traffic on an
interface, leave it unchecked.
It is not recommended that you make any device that is connected to public networks, such as
the Internet, a
Trusted Device
Allow Incoming
Enabling these options allow the specified services to pass through the firewall. Note, during a
workstation-class installation, the majority of these services are not installed on the system.
, your firewall will not allow remote machines to have access to certain
Medium . You can select
allows access to your system for all traffic from that
Trusted Devices
.
to allow specific services
Customize
Customize to allow specific services through
eth0
as trusted means all traffic over the
eth0
and any traffic coming
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