linux as firewall server

[jakhan]

dear folks

i would like to know basic steps in making linux as a firewall server, please mention how do i map ports to IP addresses. also tell how to implement NAT.

thanks

Jahangir

 

[BIS]

That is quite a lot to put here...
I think you are better of to go here:

http://www.netfilter.org/

and start reading the howtos and FAQ's.

Or alternatively:

http://firestarter.sourceforge.net/

 

[santoshdj123]

Hi

If u r configuring linux as a firewall then following are the commands considering as eth0 is your linux server's NIC for incoming while eth1 is outgoing

# iptables -t nat -F POSTROUTING
# iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
# echo "0">/proc/sys/net/ipv4/ip_forward


santosh

 

[tarn]

To save yourself some time see:

http://www.linux-firewall-tools.com/linux/firewall/index.html

Use it to build your firewall and then analize it to see how its done :¬)

Good Luck
Laurie.

 

[Trekkie]

if you only know the basic linux commands, perhaps downloading smoothwall. it's gui interface pre-made firewall.

http://www.smoothwall.org/

G.L.

Tk.

 

[idiotboy]

Might I suggest

http://www.smoothwall.org

Its a super little firewall that is Linux based. I have installed mine on an old pc that I had lying around the house. I have it running on an old 486 (the minimal install is about 40mb hard drive 8mb ram or something similar).

I found that trying to impliment security on Linux is a very difficult task and one that can cause a multitude of problems.

Smoothwall is free, so the only cost is the box and 3 network cards. I have four machines hooked into my hub which points to my firewall. With the recent hit of viruses etc, I have as yet no impact (touch wood).

It has as much security that you will ever need and more importantly has very clear install/step by step based guides.

 

[RACM]

Another option is censornet.

http://www.censornet.com

It is a complete and dedicated firewall package. Extremely easy to install and setup.