[netbios]

I had just recently installed Red Hat 9.0 and also a newbie to the Linux World.I'm hoping to learn bits and pieces as I go along.I like the OS so far but there are a few issuses I want to ask.My biggest concern is security.I found where I can set my system security with the low,medium,and high settings.I did a UDP scan at Sygate and had all ports OPEN.Is there a way to block them?The TCP ports where all good except for ICMP.

Overview:How can I block UDP ports? How can I block IMCP?

I seen on my security settings that you can customise but there wasn't an array of ports listed and didn't see anything to put in my own.

Thanks,NetBios

[Squashman]

If you really want to learn more about firewalls you are going to have to use Iptables or Ipchains. That way you can write your own firewall script. Basically what you do is Deny everything coming in then decide what you want to allow in. Basically I just let in Ports 22, 80, and 443.

I took a class on Internet Security and Firewalls at my local Technical College.

[codejockey]

The Squashman has it right. You can also go to routers and hardware firewalls, but the principles are exactly the same (although capabilities and details may differ a bit). A good source of information is the Linux-HOWTOs, guides and FAQs, currently in residence at: www.tldp.org

Hope this helps.