30/09/2018, 18:05

How to open port Ubuntu 14.04?

I use nmap tool to scan all port on my computer, but all 1000 scanned port are closed. Like the following result:

Nmap scan report for minhvu (192.168.1.3)
Host is up (0.00026s latency).
All 1000 scanned ports on minhvu (192.168.1.3) are closed

Nmap done: 1 IP address (1 host up) scanned in 0.06 seconds

And then i scanned for daynhauhoc.com, i got this

nmap daynhauhoc.com

Starting Nmap 6.40 ( http://nmap.org ) at 2015-09-08 11:54 ICT
Nmap scan report for daynhauhoc.com (128.199.206.246)
Host is up (0.052s latency).
Not shown: 997 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
2222/tcp open  EtherNet/IP-1

Nmap done: 1 IP address (1 host up) scanned in 2.03 seconds

How can i actively open a specific port?

Jack Vo viết 20:17 ngày 30/09/2018

Did minhvu computer permit scan port or not ?
Are you using any antivirus software like AVG, Kaspersky …etc ? If have, should try to disable antivirus and run nmap again ?

... viết 20:05 ngày 30/09/2018

nmap tool just a program that’s allow user view the list of opened port on a server, it’s not use to open a port on server.

I use Ubuntu 14.04, so i don’t use any anti-virus software.
Maybe all ports are default closed. I don’t know how to open port to telnet from another computer.
In java or C++ programming, i can do this, but not on Ubuntu terminal.

Jack Vo viết 20:19 ngày 30/09/2018

On ubuntu, they have soft-firewall, called iptables. You can check this service is running or not.
Some default services was enable when you installed Ubuntu in the first time. I guess : ftp, ntp or telnet, SSH.
Try to run cat /etc/services to know which port belong to which service and check the service is running or not ? Should google first to know some tutorial nmap