[CentOS] Using a CentOS 6 Machine as a gateway/router/home server

Sun Jun 28 19:32:31 UTC 2015
Brian Miller <centos at fullnote.com>

On Sun, 2015-06-28 at 14:50 -0400, Max Pyziur wrote:

> I haven't setup the firewall yet (dangerous, I know) until I get the 
> connectivity working.
> I'm obviously overlooking some other configuration settings required for 
> machines inside the network being able to connect through the 
> gateway/router.

As others have pointed out, you're either missing a NAT layer or you got
a large enough IP allocation to subnet and you haven't set up routing.
Probably safe to assume it's NAT.

I'd suggest at a minimum you install something like shorewall to assist
in managing your firewall and IP masquerading tasks.  It's available in
EPEL, is very well documented, and provides enough built in sanity
checks to protect you against making some silly (and some not so silly)
mistakes in your firewall management.