IPCHAINS continued

[Frederic Breitwieser <frederic.breitwieser@xephic.dynip.com>]

Still playing with my firewall project, and having a lot of fun.

Here is what I've done so far.  When ppp0 dials into the internet, it makes
a connection, and runs ip-up script, which I've added the following commands:

# allow internal boxes out through the 3c509b card, all ports.
ipchains -A input -i eth0 -j ACCEPT

	# allow http in
	ipchains -A input -d $1 80 -j ACCEPT -p tcp
	# allow ftp in
	ipchains -A input -d $1 21 -j ACCEPT -p tcp
	# allow pop3 in
	ipchains -A input -d $1 110 -j ACCEPT -p tcp
	# allow smtp in
	ipchains -A input -d $1 25 -j ACCEPT -p tcp
	# allow mta in
	#ipchains -A input -d $1 ??? -j ACCEPT -p tcp

The above configures what tcp ports I allow in my firewall.  This is good,
this works, and that's swell.

Now, the above ports have to be routed or forwarded to hidden private IP
addresses, like so:

	# forward http
	ipportfw -A -t $1/80 -R 172.16.0.20/80
	# forward ftp
	ipportfw -A -t $1/21 -R 172.16.0.20/21
	# forward pop3
	ipportfw -A -t $1/110 -R 172.16.0.20/110
	# forward smtp
	ipportfw -A -t $1/25 -R 172.16.0.20/25
	# forward mta
	#ipportfw -A -t $1/??? -R 172.16.0.20/???

Then, I close the fireall with :

	# close the rest of the linux box
	ipchains -A input -i ppp0 -j DENY

The ipportfw commands fail, returning an error message as follows:

	Setsockopt failed: protocol not available.

I scanned through the manpages, but unclear what this error means.  I'm
running Debian 2.0 (hamm?) and only want to use this PC as a firewall.

Thanks for any assistance.  See, I'm making progresses :)
Frederic Breitwieser
Bridgeport, CT 06606

Homebrew Automotive Website:
http://www.xephic.dynip.com/

Wanted - RWD Buick Flywheel that fits the 3.8L / 4.1L!
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