Software projects/OS/Slackware/Advanced usage/Firewall

Network interfaces

• eth0 is the interface that shows up when you plug an USB to ethernet adapter. A list of compatible ones is located here.
• wlan0 is the embedded Wi-fi interface.
• wlan1 is the name of a Wi-fi dongle.
• usb0 is the big USB port (not sure, may be the first plugged).
• usb1 is the small USB port (not sure).
• there's also a bluetooth interface, but until now i never used it, so can't tell more about it.
• These interface numbers may vary, depending which one you plug first.
• The numbers can be fixed using the /etc/udev/rules.d/70-persistent-net.rules file.
• This file is deleted at each shutdown. To make use of it, edit /etc/rc.d/rc.local_shutdown , and comment this line:

rm /etc/udev/rules.d/70-persistent-net.rules

into

#rm /etc/udev/rules.d/70-persistent-net.rules

Firewall

• I shipped some default firewall configurations for eth0, wlan0 and usb0. I generated them using the easy firewall generator.
• I didn't test them as i use a router, so it's up to you to try it.
• If you want to use a firewall, ie. for eth0, then do:

cp /etc/rc.d/rc.firewall.eth0 /etc/rc.d/rc.firewall
chmod +x /etc/rc.d/rc.firewall
/etc/rc.d/rc.firewall start

Gateway

• To use the OP as a simple gateway

chmod +x /etc/rc.d/rc.ip_forward
/etc/rc.d/rc.ip_forward start

NAT Router

• It also uses a /etc/rc.d/rc.firewall script.
• I don't provide any because everyone have a different setup.
• Create it yourself with the easy firewall generator.
• Then save it as /etc/rc.d/rc.firewall and do this:

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

QoS

• For now, a recompiled kernel is necessary.
• A basic setting consists of packet mangling who changes the ToS field in the packets, through rc.firewall rules. A simple example:

iptables -A PREROUTING -t mangle -p tcp --sport ftp -j TOS --set-tos Minimize-Delay
iptables -A PREROUTING -t mangle -p tcp --dport ftp -j TOS --set-tos Minimize-Delay
iptables -A PREROUTING -t mangle -p tcp --sport ftp-data -j TOS --set-tos Maximize-Throughput
iptables -A PREROUTING -t mangle -p tcp --dport ftp-data -j TOS --set-tos Maximize-Throughput

• A more advanced setup makes use of dedicated kernel modules. The most known script is the outdated wondershaper.