Re: Firewall setting

[Jonathan Q <jq@example.com>]

Before I get answer, please start a new thread when
changing topics, don't just change the subject.  For
those with email clients that do threading, it creates
an ugly mess if you don't.  The same mess is created
in the TLUG archive, which also does threading. As
a result, your message will ever after appear in 
the thread under dhcp servers that was previously
being discussed. 

During the install, Red Hat 7.1 gives you a choice
of no firewalling, medium security firewalling, or
maximum security firewalling.  The latter two also
offer you the choice of custom exception ports that
will be allowed through.

Medium level filters the well-known ports (<1024), 
High filters just about everything, and none does
what you would expect.  

Based on your description, it would seem that you chose
either medium or high security firewalling, and did not
create any exceptions for ssh or http.  You can make
ssh and http accessible by changing your firewalling rules
to let them in.  

You can find your current rules in /etc/sysconfig/ipchains.
You can find an ipchains howto in /usr/share/doc/ipchains-1.3.10.
There is also a GUI config tool called firewall-config 
(on the System menu or run it from the command line).  I've
never used it, proceed at your own risk.  One thing I have
noted is that if I run it, it does not seem to load my
existing /etc/sysconfig/ipchains file, yet the help from
firewall-config says it craates that file, so I'm assuming
that it wipes out whatever current firewalling rules you have,
so if you value them, save them.  I'm also infering from
this that firewall-config is not far enough along in its
development to edit existing rules, only to create a set of rules
from scratch, so use at your own risk.  You might want to just
read the howto to find out what you're doing, then modify the
existing ruleset, which is doing the right thing.  You just need
a couple of exceptions for ssh and http.

Jonathan


legend (fukudam@example.com) wrote:

> Hi, I have a question about firewall. I have just installed RedHat 7.1,
> and I think from 7.1 firewall is installed by default.
> 
> I'm not that sure if this is causing the problem, but now I can't access
> all the services that run on the linux box from outside.