Firewall in Redhat Linux 9.0
 

I use Redhat Linux 9.0 (2.4.20-8). It has an inbuilt firewall and I have set the security level to medium? Is it correct and safe enough to have it on medim. I use internet though dial up connectivituy (56k-Modem).

Secondly, how strong is the firewall?

Thirdly, does it automatically configure which programs has to be given access to the internet?

The default firewall with a setting of medium is only going to disallow the most common ports, as if you were going to be running a webserver it would probably initially block off port 80.. and so on.

If your serving out anything and only going to dial out yourself to browse the internet, email.. etc.. you could pretty much close off your box to the outside world and still be ok.

Might want to read up on iptables which its most likely using by default for firewall rules.

This is a good recommendation. Read up on iptables, list your current ruleset, and make the determination if they are appropriate for how you are using your system.

I'd also like to make another recommendation: Go to the Redhat update site and get the last available updates. After that you may want to go back through and compile those applications which have security holes.