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While
an added benefit, RedHat's firewall can often cause problems
with new users to the OS. Typically they will be confused
as to why they can access the RedHat machine's web server
from the machine only. Any attempt to access this from a
remote machine causes an access error.
Distributions
that are preinstalled (such as those from Dell) are usually
set with the firewall enabled. Depending on your desired
level of security (or lack thereof) you can disable the
firewall, or only enable specific ports.
Using the lokkit Program
The
simplest way to get allow all connections to your RedHat server
is to disable the firewall. To do this, log in as "root"
and at the command line type the command "lokkit".
You can check the "No Firewall" box and then click
"OK". No reboot should be necessary.
Enabling
Servers
This will allow connections to any port of your machine.
However, it still may be necessary to turn on certain Internet
Daemons (services). For instance, if the Apache web server
isn't running, it can't serve web pages. To enable various
servers to run under RedHat Linux, use the chkconfig command.
 Click
here
to learn how to turn on servers using chkconfig.
Advanced
Information
The lokkit program simply creates rules for the firewall
to follow. Knowledge of the rules will allow you to create
a firewall that is more customized than can be achieved
using the lokkit program alone. It's important to know that
lokkit will overwrite the firewall rules file. Therefore,
you should choose either to only use lokkit, or write your
own firewall rules by hand.
The
firewall rules are stored in the file /etc/sysconfig/ipchains.
This file is read upon startup from the /etc/init.d/ipchains
init process. After modifying the /etc/sysconfig/ipchains
file, you can put the changes into effect by typing "/etc/init.d/ipchains
restart"
Lokkit
can be installed from the RedHat Network by typing:
up2date lokkit
IP
Chains can be installed from the RedHat Network by typing:
up2date ipchains
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