Hi all,

Simple questions, I hope:

How do I check if ports are open?
How do I close ports?
How do I open ports?

Thanks!

Chris

Well please use the SEARCH function. This question has been asked and ANSWERED several times!

I searched before I posted this and didn't really find squat. I'm sure it's there somewhere, but I don't have the time to go searching through the 6 million pages it came up with... Thanks anyway, I'll try to learn it on my own.

Chris

How do I check if ports are open?
"netstat -anp" gives you the protocol, port and PID of the process. "lsof -i" does output similar info. other tools are RH's "socklist" (a perl script) or a C app called "sockstat".

How do I close ports?
How do I open ports?
Use a firewall. In Linux/GNU it's called "Netfilter", tho the "userland" apps you'll be interfacing with are called "iptables" for kernels v2.4 and up, and "ipchains" for kernels v2.2 (and v2.4 if you really need).

I searched before I posted this and didn't really find squat. I'm sure it's there somewhere, but I don't have the time to go searching through the 6 million pages it came up with
If you found too many entries then try to refine your search. We got loads of scripts and threads about iptables.
Also the first thread in this forum holds some links to usefull iptables tutorials and scripts.

If you "don't have the time" then ask yourself if Linux/GNU is the OS for you. It just takes a little investment to make it work and when it does, it works damn good.