rc.firewall script problem

Hi there,

I use the sample script given in Linux IP Masquerade HOWTO (Section 3.4.1) for my Slackware box. I read from netfilter homepage that it's better to start rc.firewall right after the network is set up, so I start up the script in rc.inet2 before any network services.

I can ping the box from outside after it's up. But the WWW server and SSHd is not accessible from outside. The strange thing is that if rc.firewall starts after SSHd server and before HTTPd, SSHd is accessible from outside while HTTPd is not. If I start rc.firewall in rc.local in the last step, both services can be accessible from outside.

What should be the explaination for this strange behavior of iptables?

Regards,
A Newbie