[vox-tech] Linux networking question

[Michael J Wenk]

Answers below:

----- Original Message -----
From: "Marc Hasbrouck" <m_hasbrouck@yahoo.com>
To: <vox-tech@lists.lugod.org>
Sent: Saturday, January 25, 2003 9:58 PM
Subject: Re: [vox-tech] Linux networking question


> What version of Linux are you using?

Debian linux woody with kernel 2.4.19.


>
> For a generalized look at firewalling, look around for
> the O'Reilly book Building Internet Firewalls, 2nd Ed.
> It gives a non OS specific discussion of firewalling
> and ports. Also, go to netfilter.org (the iptables
> folks).

I've read some of their stuff, and went thru the manpages, but
unfortunately, I wasn't able to do what I wanted to do.

>
> If you have your DHCP server and clients set up right,
> local traffic should stay local. At least it does here
> on my systems.
>
> An example of the kind of addressing I use:
>
> Local network:
> IP adddresses: 192.168.100.1 through 192.168.100.254
> Net Mask: 255.255.255.0
> Default Gateway: 192.168.100.1

Right now, Im completely DHCP, but my windows box, and the PS2 are given
static addresses via DHCP.

A little quirk of mine is to use the 10.0.0 network, and my static
addresses(granted by DHCP) are below 40, dynamic are 40-80, and everything
above 80 is non DHCP.  I use a standard class C subnet mask, and my default
gateway is my linksys router which is 10.0.0.200.  I hand everybody on DHCP
DNS servers 10.0.0.1(linux box), and whatever is in resolv.conf(comcast.net
nameservers)

My original solution did not work, and that was to turn kernel level
netfilter logging on, and then figure out what ports individual games wanted
open and then open them.  It didn't work because no matter what I did to
iptables and syslog, everything iptables would find would be logged to the
console only.  I wasn't able to figure it out, and combing the manpages(and
even some of the netfilter sourcecode) didn't help.  Even with that, I was
looking for more of a general way to grant the ps2, rather than individual
port forwarding which is sorta tedious.

Ill check out that book sometime soon, thanks for the suggestion.



>
> When I reference an address out side of the above
> range, the packet is routed to the gateway (in this
> case, 192.168.100.1). Otherwise, the packet should
> never cross the gateway.
>
> Marc
>
> --- Michael J Wenk <mwenk@comcast.net> wrote:
> > I have a question that has cropped up recently.  I
> > have a gamesystem with an ethernet card in it.  My
> > old setup had everything going thru my linux system
> > to the internet.  The linux box has a DHCP and
> > caching DNS server running and it all seemed to work
> > great.  I have had this setup since December of 2000
> > and have had to make little modifications to it.
> > Unfortunately, my PS2(the above game system) does
> > not seem to like this very much.  The issue is
> > unfortunately port forwarding.  To fix this(on a
> > temporary basis) I used the router portion of my
> > hub(its a linksys cable/DSL router that I bought a
> > few years back on the hopes that it would work
> > better or at least as well as the linux in routing,
> > and save me a few bucks on power.  Unfortunately
> > back then, it failed miserably.  However, recently
> > with my current problems, I was reading that the
> > thing is upgradable by firmware.  I did that and it
> > works better.  Rather than fail after a few hrs of
> > operation, it lasted about a week before requiring
> > powercycling.  My problem is more software and comes
> > from the fact that game makers for PS2 don't seem
> > very communicative about what ports need to be
> > opened in their software for stuff to function
> > properly.  The linksys router supports a DMZ host
> > which throws the PS2 system on the network
> > unprotected.  My question is, is there a way to do
> > this in software in the linux box?  I know I could
> > probably get 1 more hub, and put the exterior
> > connections(the PS2 and the linux box) on it and get
> > another IP from comcast.  I don't want to do this
> > for my whole network, and it comes from the fact
> > that I never could convince my systems that they
> > didn't need to go to the internet for local file
> > xfers(which I do a lot.)  So, does anyone have any
> > idea how to simulate the DMZ portion of the linksys
> > router under linux?  Im running a 2.4 kernel(2.4.19
> > to be exact.)  Oh, and I'm looking for something a
> > bit cleaner than just forwarding every port to the
> > PS2.
> >
> > Mike
> >
>
>
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