How Can You Test If A Port On Your Firewall Is Open?

When I dont know for sure, I just run a scan against it.  There are several out there, like NMAP, etc, but they are easy to use.  Keep those firewalls secure.  Below, you see me trying to determine if SSH is open or not, using NMAP via CLI.

In CLI, this is what I did.  For a closed SSH port:
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C:\NMAP\nmap-6.40-win32\nmap-6.40>nmap -p 22 5.5.5.5

Starting Nmap 6.40 ( http://nmap.org ) at 2014-03-18 09:53 Central Daylight Time

Nmap scan report for 5.5.5.5
Host is up (0.0059s latency).
PORT   STATE  SERVICE
22/tcp closed ssh

Nmap done: 1 IP address (1 host up) scanned in 2.08 seconds
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For an open SSH port:
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C:\NMAP\nmap-6.40-win32\nmap-6.40>nmap -p 22 97.97.97.97

Starting Nmap 6.40 ( http://nmap.org ) at 2014-03-18 09:56 Central Daylight Time

Nmap scan report for 97.97.97.97
Host is up (0.0046s latency).
PORT   STATE SERVICE
22/tcp open  ssh

Nmap done: 1 IP address (1 host up) scanned in 2.18 seconds

C:\NMAP\nmap-6.40-win32\nmap-6.40>
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