Home / server / Questions / 1094649
In Process
Tymur Gubayev
Asked: 2022-02-25 01:11:25 +0800 CST

nmap reports ftp port open when the server is actually shut down

  • 772

nmap output:

$ sudo nmap -PN 1.2.3.4
Starting Nmap 7.92 ( https://nmap.org ) at 2022-02-24 09:58 CET
Nmap scan report for 1.2.3.4
Host is up (0.035s latency).
Not shown: 999 filtered tcp ports (no-response)
PORT   STATE SERVICE
21/tcp open  ftp

Nmap done: 1 IP address (1 host up) scanned in 8.80 seconds

This happened twice now, with a server that was literally not running because it hat no power, and now another one - which actual state I don't know exactly, there is most probably some firewall between. Neither server has anything ftp related.

Actually, checking ftp on any IP reports either open or filtered, but always Host is up.

I'm guessing there is something in our network causing this effect, but I have no idea how would I actually find out, what is it. Please help.

nmap

0 Answers