Why are these ports being filtered on my new installation?

October 14, 2016 2.1k views

I created a new droplet (Ubuntu 16.04.1) and right after it was created I ran nmap on it to see the open ports. Obviously ssh on port 22 is expected, but I don’t know why the other ports are showing up. Can anybody shed some light on why these ports were showing up as filtered?

user@local_machine $ nmap -A -p- vps_remote_address

Starting Nmap 7.01 ( https://nmap.org ) at -
Nmap scan report for vps_remote_address
Host is up (0.022s latency).
Not shown: 65530 closed ports
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.1 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| Removed (RSA)
|_ Removed (ECDSA)
25/tcp filtered smtp
135/tcp filtered msrpc
6666/tcp filtered irc
6667/tcp filtered irc
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 30.22 seconds

1 Answer

Are you sure that you did a clean install of a new droplet?

If you create a new droplet with one of our base Ubuntu installations you should only have port 22 open remotely, and you can check this from the Droplet directly via the following:

root@droplet:~# netstat -tulpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0    *               LISTEN      1464/sshd       
tcp6       0      0 :::22                   :::*                    LISTEN      1464/sshd       

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