Some firewall questions

[ampm2003]

Hi people; i hope someone can help me with this.
Well in fact i am asking more to learn than to my concern of haveing some few open ports;
the thing is that I've got a Red Hat 6.0 box, with a 2.2.16 kernel (really stable; this is the secound year that the PC stays non stop with no clashes at all); and have it programed to be a "router"; I've programed it with IPchains because IPtables had not been released yet; and have the IP masquerading service.
Well the question is this one:
which are the ports that need to be open so that i can run ip_masquerade service?
I've got the 53, 443, 515, 1080, 5190, and 8080 ports open and i am sure that not all of them need to be opened to have the IP_masquerading service working; for example the 515 (spooler port; which I supouse has nothing to do with masquerading doesn't need to be open).
The second question; is how do i close those ports; which services should i kill to close those ports; or should i touch the inet.d file?
Well i hope someone can help me with this...
thanks.
ampm2003

[slarty]

You don't need any open ports to use the ip masquerade service. It's a type of routing, and has no interaction with the host networking.

As far as "how do I close ports" is concerned, please see another one of the million or so threads on this topic

By the way this thread should probably be in another forum, like network security or unix security.

[MrLinus]

First, some thoughts.

IPTables has been released (http://netfilter.org).

You really should update your kernel. There are a lot of vulnerabilities out there. Just because you believe it works fine doesn't mean that someone hasn't been through.

I'd recommend switching from IPChains to IPTables. The static nature of IPChains makes it a weak firewall.

Now, slarty answered your question about the IP_Masquerading. All that IP_MASQ is, is NAT. It is translating addresses internally to external. It is part of the firewall rules and is not a service.

Elimenate the ports that don't need to be available on the internet. Really, looking at your ports I'd say only port 53 (outbound /inbound to get to DNS), port 443 (for HTTPS and SSL) and port 8080 (assuming you are offering webservices out).

A question though: what is this box for? Webserver?

Originally posted here by ampm2003
Hi people; i hope someone can help me with this.
Well in fact i am asking more to learn than to my concern of haveing some few open ports;
the thing is that I've got a Red Hat 6.0 box, with a 2.2.16 kernel (really stable; this is the secound year that the PC stays non stop with no clashes at all); and have it programed to be a "router"; I've programed it with IPchains because IPtables had not been released yet; and have the IP masquerading service.
Well the question is this one:
which are the ports that need to be open so that i can run ip_masquerade service?
I've got the 53, 443, 515, 1080, 5190, and 8080 ports open and i am sure that not all of them need to be opened to have the IP_masquerading service working; for example the 515 (spooler port; which I supouse has nothing to do with masquerading doesn't need to be open).
The second question; is how do i close those ports; which services should i kill to close those ports; or should i touch the inet.d file?
Well i hope someone can help me with this...
thanks.
ampm2003

[ampm2003]

Thanks for your help; yes; i should really go into IPTables; but with my studies, i haven't got much time to do so... Regarding MsMittens question; the linux box is only used as a router...
well peolpe thanks again...
ampm2003