Port safety basics

[enewmen]

Hi all.

It seems I don't understand this as well as I thought. I also got a IP Black List (already did lots of malware scans) which got me paranoid who is looking at my NAS.

What I'm trying to do is make sure ALL ports are properly closed/sealed on my router - including port 25. Only the most necessary can be opened. 80, 5000 (my NAS, etc)
Then remotely check if all the ports I think are closed really are closed.

What online tool do you recommend to check if all (wide range) ports are correctly closed?

I did "command-prompt" netstat -a That showed about 20 ports on my router in a ESTABLISHED state to strange IPs. port 55800, 55810, etc.
The local host and 0.0.0.0 is in a LISTENING state - seems OK.

Any ideas or point me in the right direction?
I have a Asus RT-N66U (and others) please use that reference to show me where to look.

Thanks!
PLEASE Assume I'm a idiot and need step-by-step instructions.

 

[thiggins]

Good ol' Shields Up should tell you what you want to know.

I would not operate any web service on port 80 or 8080. Move it to a more obscure port and use HTTPS only.

 

[enewmen]

Thanks for the post!

I tried Shields Up. No problems found.

So if I don't open or forward ports myself - then all others should be safely closed/sealed?

Yes. If I must open or forward any port, only use HTTPS with a certificate or SFTP, etc.

I still have the IP blacklist. But since there are no infections found on my PC or NAS, it should go away later.

 

[stevech]

UPnP is disabled on the router?

 

[enewmen]

UPnP is disabled on the router?

YES.
Disabled and not used for any reason.