Maximum PC

I am looking to build a linux based firewall/router for my home network (which will be re-done over the christmas break from school). I currently connect to the net via dial up. (yes, archaic and slow, but thats what you got). I want that to function as a gateway that will constantly keep the internet connection alive (on second phone line) or dial out when requested.

Also all of the other machines (save maybe two, one being a windwos server and the other being FC3) will be WIN XP Pro.

I will also have a linksys wireless AP for my laptop to connect to.

My network went down while trying to add the AP, everything went wack and stopped working. (Computers could not see/ping one another etc etc)

So, I want to have a single computer control the internet connection, the routing needs (was originally handled by the XP machine connected to the internet) as well as provide a firewall due to an almost constant connection.

Distro of choice will probably be FC3 and the machine will probably be somethiong along the following:

• Celeron 800mhz
• 512mb SDRAM
• Either a 10 , 15, or 20gb HDD (depending on need)
• GeForce 4 MX440 <-- DOH! GeForce 2 something not 4 MX440.
• CDRW Drive
• Appropriately compatable modem
• 2-3 NICs (depending on need)

I know somewhat of how to navi through FC, but I am unsure how to go about configuring iptables etc. I have not found much current, useful information on how to set something like this up to share a dial up connection (becuase who would want to do that! arrr! haha.)

All input is appreciated. Thanks!

i dont use dial up. but...in theory it should be the same.

A Network card is normally called eth0 under linux. I am guessing that your modem will be ppp0 or something like that. SOmeone with linux modem experience correct me on that one.

Regardless, you are going to need a switch in which all your computers in your private network attach to.

That switch will be uplinked to your nat box. Probably connected to eth0.

So all you got to do now is forward packets from eth0 to ppp0.

You are correct about iptables. Iptables is the native program that works with the kernel to nat/route/mangle/drop/etc packets.

You can get detailed information here:
http://en.tldp.org/HOWTO/IP-Masquerade-HOWTO/

but, if you are already somewhat familiar with iptables, here are the core iptables parameters that you will need:
(substitute $EXTIF with external interface (ppp0 - or whatever) )

IPTABLES -A FORWARD -i $EXTIF -o $INTIF -m state --state ESTABLISHED,RELATED -j ACCEPT
IPTABLES -A FORWARD -i $INTIF -o $EXTIF -j ACCEPT
IPTABLES -A FORWARD -j LOG
IPTABLES -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE

I didnt find anything on those forums about my mobility 9600... there was a little blip about not having 3d acceleration (which is ok, becuase all of my games are windoze games anyway).