How to find out firewall working or not?

[olddocks]

I am newbie to linux and last night i installed APF firewall in my server. Actually i dont know whether it is working or not. how to find out generally firewall is working or not?

Thanks

[RobinVossen]

Well this is one of the oldest Questions in the book.
First portscan it.
Then you can test it with hping.

Portscan will show what is open and what closed.
And with hping you can check more advanced stuff like only SYN packages are allowed or not.

Hope that helped.
Cheers,
Robin

[Lazydog]

You could also look at them with this:

iptables -L -v -n | less -SCi

[NomiUnger]

Hey @olddocks,

Since you are a newbie (and we all know what that’s like ) and managing Linux firwall/iptables can be daunting, so maybe you might want to opt for an easier way to manage your Linux iptables, at least for now.
There are several front-ends for Linux iptables that you can use. For example, there’s GUFW (look up in Ubuntu community), which is a simple front-end, and you also have dome9.com/security-challenges/ubuntu-firewall-management, which is a cloud-based ubuntu firewall solution that manages the firewall for you transparently. Check out those options and see what suits you best.
I would also suggest reading up on iptables, just to get a better understanding of how they work. It might also help in choosing a solution

Good luck! Nomi

[oz]

Guys, this thread is nearing 5 years old so I'm going to go ahead and close it, but do feel free to start fresh threads with the details if any of you are still having problems with Linux.

Thank you.