unable to configure firewall using IPTABLES

adityavpratap · 05-27-2006, 07:45 AM

Hi friends,
I have been trying to set up a firewall using IPTABLES as per the method described in the following link -
http://www.howtoforge.net/custom_iptables_firewall
However, I think that the method described is RedHat specific, or atleast it requires some modifications to be adopted for Slackware. For example the firewall.iptables script must be rc.firewall.iptables located in /etc/ instead of /etc/init.d/, (I hope I am not wrong).
However, chkconfig is not found on my installation of Slackware 10.1. I have been trying to locate the package without any success.
Besides after having followed the procedure described in the link mentioned supra, when I do -
$ sudo /etc/rc.firewall.iptables start
I get the following rather lengthy output on my terminal and the firewall prevents all access to internet. Here is the output -

Quote:

Starting Firewall services
firewall: Configuring Firewall Rules using iptables
Bad argument `DROP'
Try `iptables -h' or 'iptables --help' for more information.
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Banned address/network file not found.
firewall: IANA-reserved address/network file not found.
firewall: Local rules file not found.
firewall: Outbound ping enabled
firewall: Inbound ping enabled
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: DNS client enabled
firewall: ** No secondary DNS configured **
firewall: DNS Full server enabled
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Auth client enabled
iptables: Unknown error 4294967295
firewall: Auth server enabled
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: SMTP Local server enabled
iptables: Unknown error 4294967295
firewall: Remote site any/0 may access local POP-3 server
/etc/rc.firewall.iptables: line 963: [: -gt: unary operator expected
/etc/rc.firewall.iptables: line 990: [: -gt: unary operator expected
/etc/rc.firewall.iptables: line 1058: [: -gt: unary operator expected
/etc/rc.firewall.iptables: line 1084: [: -gt: unary operator expected
iptables v1.3.5: host/network `my.news.server' not found
Try `iptables -h' or 'iptables --help' for more information.
iptables v1.3.5: host/network `my.news.server' not found
Try `iptables -h' or 'iptables --help' for more information.
iptables v1.3.5: host/network `my.news.server' not found
Try `iptables -h' or 'iptables --help' for more information.
iptables v1.3.5: host/network `my.news.server' not found
Try `iptables -h' or 'iptables --help' for more information.
firewall: Clients may access remote NNTP server: my.news.server
iptables v1.3.5: host/network `your.snews.server' not found
Try `iptables -h' or 'iptables --help' for more information.
iptables v1.3.5: host/network `your.snews.server' not found
Try `iptables -h' or 'iptables --help' for more information.
iptables v1.3.5: host/network `your.snews.server' not found
Try `iptables -h' or 'iptables --help' for more information.
iptables v1.3.5: host/network `your.snews.server' not found
Try `iptables -h' or 'iptables --help' for more information.
firewall: Clients may access remote secure NNTP server: your.snews.server
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote TELNET servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote SSH servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Remote site any/0 may access local SSH server
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote FTP servers
iptables: Unknown error 4294967295
firewall: Clients may access remote HTTP servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Remote client any/0 may access local HTTP server
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote HTTPS servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote FINGER servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote WHOIS servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote GOPHER servers
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote WAIS servers
iptables: Unknown error 4294967295
firewall: Real Video client enabled
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
firewall: Clients may access remote PPTP servers
firewall: Outbound TRACEROUTE enabled
firewall: Inbound TRACEROUTE enabled
firewall: NTP Client enabled
firewall: ICQ Client enabled
firewall: Masquerading internal network
done

Being a total newbie in this regards, I am unable to make either head or tail of this.
When I google for "iptables: Unknown error 4294967295" I found a site that suggested that I recompile the kernel with the parameter CONFIG_IP_NF_TARGET_NETMAP=y in the relevant .config.
However the error message fails to go away even after I recompiled the kernel as suggested.
I hope somebody out there can help me out.

dennisk · 05-27-2006, 08:02 AM

Slackware looks for a firewall scrift in /etc/rc.d/rc.firewall. A good starter firewall for a typical desktop machine is Brian Hatch's 10 Minute firewall. You can find the script here http://www.hackinglinuxexposed.com/a.../20030709.html

Make the script executable with

Quote:

chmod a+x /etc/rc.d/rc.firewall

and then restart iptables with

Quote:

/etc/rc.d/rc.firewall restart

That's it.

dennisk

Alien Bob · 05-27-2006, 08:09 AM

Another way to create a rc.firewall script is to open http://www.slackware.com/~alien/efg/ where you find the "Easy firewall Generator" slightly modified so that the generated script works with Slackware.
Just answer a few basic questions about your server setup, and the script will be generated - you can copy and paste it into a file called /etc/rc.d/rc.firewall (this specific filename and none other).
If you do

Code:

chmod +x /etc/rc.d/rc.firewall

then the Slackware init scripts will automatically run it when your computer boots.

Eric

drkstr · 05-27-2006, 11:19 AM

also, make sure to 'chmod +x /etc/rc.d/rc.ip_forward' if your firewall will also be serving as a router for other computers on the local network.

regards,
...drkstr

adityavpratap · 05-27-2006, 10:12 PM

Thanks to your prompt replies, I have now got a working firewall. :-)

nutronix · 05-29-2006, 10:21 AM

thank you guys i got it working too....good thread