NMAP: All ports open?

[peci1]

I had this problem with PPtP VPN setup - the tutorial said to add a firewall rule to accept all traffic from ppp* interfaces (because the VPN driver creates interfaces ppp0, ppp1 etc.), so I configured it like that, but the tutorial author did not imagine someone could connect to WAN via PPPoE, which creates interface pppoe-wan. So I really had all ports open to the internet because of this tutorial. So the risk that @Tomov did some similar configuration mishap and really has all ports open is real.

[vcunat]

Is it worse than trying some nmap web tools on the internet?

[peci1]

Giving it out on a forum full of tech-savvy people? I would say yes (but I also have high belief in the ethical orientation of most users of this forum )

[petrcerny]

@peci1

One thing is having a running service listening on an open port, and the other is blocking access to the port from WAN.

Sorry, I don’t get it. There is no open port without a service. Ports aren’t just open, but you need a process that binds it. The OP explicitly asked about why nmap shows almost all ports as open. It still looks like a false positive and looking at the running services, one should immediately see the ports that are really open.

@Tomov

Is there anyone here who understands nmap well?

The parameters -sA and -sF set TCP flags. -sA is a TCP ACK scan, -sF a TCP FIN scan. You may look at how TCP handshakes work and what nmap does in each case.

[Tomov]

Guys sorry for the late reply.
I am sick and I was without internet

@talisker

In private Message of course
And I will give you mine, like this you can follow the logs.
But I fully understand, if your are not confortable with that …

We’d better leave this point out of the way.
If I ever have a break-in, I won’t think about you
Thank you for your understanding.

@fantomas

it’s a turris, it should be safe.

They used to say the same about Cisco and the Pentagon
There is only one secure network hardware in the world: Disconnected from the network

@talisker

And by the way what is the result of ShieldsUP! at https://www.grc.com ?

Stealth

@vcunat

You give the IP to all “sites” you visit. I can’t see a significant risk, though you perhaps don’t want to post it publicly.

No, I use a VPN for all my activity in my country.

@peci1

So the risk that @Tomov did some similar configuration mishap and really has all ports open is real.

I am not sure yet, but I am starting to suspect false positives due to my fault = incompetent use of nmap.

@vcunat

Is it worse than trying some nmap web tools on the internet?

I tried everything that came to my mind (tools available on the Internet and independent work).
The results were so varied that I was amazed.

@petrcerny

looking at the running services, one should immediately see the ports that are really open.

Unfortunately, I don’t know how to check it. I’m tired of it

[vcunat]

@Tomov

@talisker

And by the way what is the result of ShieldsUP! at https://www.grc.com ?

Stealth

@vcunat

You give the IP to all “sites” you visit. I can’t see a significant risk, though you perhaps don’t want to post it publicly.

No, I use a VPN for all my activity in my country.

Then I hope you put your real IP into those web tools and didn’t make them test open ports of your VPN provider.