[CentOS] Problem with CentOS server: am I running a firewall?

Wed Apr 16 10:50:26 UTC 2008
Timothy Murphy <gayleard at eircom.net>

On Wednesday 16 April 2008 12:25:35 am Timothy Murphy wrote:
> On Tuesday 15 April 2008 11:48:00 pm Filipe Brandenburger wrote:
> > >  Unfortunately, I have not been able to set it up
> > >  to allow local machines to access the internet.
> >
> > Did you enable routing? The output of "cat
> > /proc/sys/net/ipv4/ip_forward" must be 1, otherwise the server won't
> > route packets between networks. In some cases (depending on your
> > Internet modem/router) it's possible that you'll need to configure the
> > server to do NAT as well.

I found in the end this wasn't the issue;
shorewall sets /proc/sys/net/ipv4/ip_forward to 1 by default;
I only read it as 0 because I had stopped shorewall.

My error was that I had not added my LAN to /etc/shorewall/masq .
Just a silly oversight.