In my Slackware 12.2 I use PPPOE to connect my machine to Internet. In /etc/ppp/pppoe.conf I changed ETH=eth1 to eth0, USER=bxxxnxnx@sympatico.ca to valid user, and FIREWALL=NONE to FIREWALL=STANDALONE. When I run pppoe-start command as root firewall starts. When I run that command as regular user firewall doesn’t start. I registered /usr/sbin/pppoe-start, /usr/sbin/pppoe-stop, as well as /usr/sbin/iptables programs in /etc/sudoers. I prepared also appropriate aliases. I’m pretty sure I ran pppoe-start command as regular user earlier and firewall started properly. Now it doesn’t work. I have no idea what should I do to get firewalled connections to Internet as regular user. Every help will be appreciated.

Manage your firewall with a GUI tool like guarddog or something else.

That is it.

Why should regular users have the capability to start pppoe?
There is a security risk involved.

Well... Firewall for PPPOE connection is ready out of the box in Slackware. There is no need to configure it for basic usage.

I can run PPPOE as regular user using pppoe-start command and then run firewall using /etc/ppp/firewall-standalone script (after changing mode bits of the last script to executable).

I can run it also using su -c /usr/sbin/pppoe-start command. In that case pppoe-start runs firewall automatically.

In the first case I have to run firewall manually. In the second case I have to use root's password. I wonder if it's possible to run PPPOE as regular user using pppoe-start command which starts firewall automatically without using root's password.

There is no security risk because that regular user it's me. There is no difference whether I start PPPOE connection as regular user or I do it as root. Both cases are equally secure assuming I started firewall.