[CentOS] DNS or firewall problem

[Thomas Dukes]

> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of Timothy Murphy
> Sent: Monday, July 05, 2010 10:11 PM
> To: centos at centos.org
> Subject: Re: [CentOS] DNS or firewall problem
> 
> Thomas Dukes wrote:
> 
> >> Do u have ipv4 forwarding on in your /etc/syscttl
> > 
> > Uhhh, in /etc/sysctl.conf,
> > 
> > net.ipv4.conf.ip_forward = 0  ??
> > 
> > change to = 1 ??
> 
> I have more or less the same setup as you, and I have
> 	net.ipv4.conf.ip_forward = 0
> in /etc/sysctl like you,
> but I have no problem accessing my server from my laptop.
> 
> I am running shorewall,
> and it would be easy to set this up
> to have the effect you describe.
> 
> I have the line
> 	loc             $FW             ACCEPT
> in /etc/shorewall/policy .
> The default is
> 	loc            $FW             REJECT          info
> which would have the effect you describe.
> 
> Nb I don't really understand iptables,
> but I find shorewall does most of the thinking for me.

I use the iptables firewall rules in the linux ip masquerade howto. Been
using it for years without a hitch.

http://www.tldp.org/HOWTO/html_single/IP-Masquerade-HOWTO/#RC.FIREWALL-IPTAB
LES-STRONGER

I looked at shorewall some time ago but like you, I was confused with
iptables.