What is correct way to test open ports?

[chudak]

Hello,

Who do you trust when do open ports testing?

I test 3 ports 80, 443 and 32400 (forwarded) with https://www.yougetsignal.com/tools/open-ports/ (from remote machine) and  with Diagnostics/Test Port and getting =>

https://www.yougetsignal.com/tools/open-ports/

80 closed
443         closed
32400 open

Diagnostics/Test Port

80 open
443         closed
32400 closed

???

[heper]

you should always test ports from wherever location you wish it to be open or closed.

so basically:

from lan: port80 will be open by default
from externam: port80 will be closed/filtered by default

[Gertjan]

@chudak:

Who do you trust when do open ports testing?

There is one.
The most famous one actually - for years if not decades.
https://www.grc.com/x/ne.dll?bh0bkyd2

[johnpoz]

I just use canseeme.org for single port tests..

As some sort of scan to my own box.. I know what is open.. I can see what is listening.  Why would I need to do a full port scan?  But sure I have used grc.com before to show a point.  But if I needed to do it would just run nmap off a server have on the internet (multiple vps all over the place)

[kpa]

@Gertjan:

@chudak:

Who do you trust when do open ports testing?

There is one.
The most famous one actually - for years if not decades.
https://www.grc.com/x/ne.dll?bh0bkyd2

GRC port scan is good but take their other scans with a pinch of salt.

[Waqar.UK]

GRC also allows you to choose which port to scan as well.