Sudo apt install nmap Perform a Scan Despite being such a simple command-line tool, NMAP has tons of options to under varying circumstances. You’re not going to need them all for this, but they might be worth experimenting with on your own network for learning purposes. All that you need to do here is perform a simple scan of your own computer.

NMAP will search through the most common ports on your computer and see which ones are open and in use. In order to scan your computer you’re going to need its IP address. If you don’t know it, run ifconfig in a terminal to find it.

Once you have your computer’s IP, you can use it to scan with NMAP. Sudo nmap -sS -O 192.168.1.100 Substitute your computer’s IP into the command. NMAP will take a few seconds while it scans your computer, it’ll show you which services are running on which ports and whether or not those ports are open.

Mac OS X comes with a bundled port scanner tool, just one of a variety of features tucked into the ever useful Network Utility app. That means you don’t need to bother with the command line or install more advanced tools like nmap to quickly scan for open ports on a given IP or domain, instead you can.

(They’ll all be open.) It’ll also try to tell you what service is using that port. That’s a very important piece of information. Make note of it if NMAP can discover the service. If you want more information about your computer from NMAP, try using the -A flag to aggressively scan it. Visual studios 2015 for mac. Sudo nmap -sS -O -p- 192.168.1.100 Ports Take a look at the open ports that NMAP discovered.

Do you know what they all are? Are you using all of them regularly? If you answered “No” to either question, it’s worth investigating. First, Ubuntu and other Debian-based distributions handle services in a weird way. They start every program that runs as a service automatically as soon as it’s installed.

While that might seem convenient, it really doesn’t make sense. You’re never going to want to run an un-configured service on a server, so you’ll have to take the service down immediately to configure it for regular use anyway. It also creates a problem with “phantom” services running without the owner’s knowledge.

Package managers pull in tons of dependencies when they install a program. Most of the time you don’t read through all of them, especially if you’re in a rush. That means that you can have services running in the background on your computer without your knowledge or consent. That may be the cause for any unknown open ports that you discovered.

Here are some of the most common ports in use on Linux systems: • 21 – FTP • 22 – SSH • 25 – SMTP (sending email) • 53 – DNS (domain name service) • 80 – HTTP (web server) • 110 – POP3 (email inbox) • 123 – NTP (Network Time Protocol) • 143 – IMAP (email inbox) • 443 – HTTPS (secure web server) • 465 – SMTPS (send secure email) • 631 – CUPS (print server) • 993 – IMAPS (secure email inbox) • 995 – POP3 (secure email inbox) There are more, of course, and if you find one totally out of the ordinary, look it up online. If you find any one of these running when you’re not intentionally running that service, shut it down. Shutting Down Services So you’ve uncovered a couple of unwanted services running on your computer. That’s not a big deal. You can use Systemd to shut them down and disable them so they don’t run on startup the next time you boot up your computer.

If Something Seems Wrong You might have stumbled onto something really suspicious. Sometimes it’s nothing to be concerned about, other times it can be. To make sure that it’s not something that’ll harm your computer or do something about it if it is, you’ll need to scan your computer for viruses and rootkits. Before you doubt the possibility, Linux machines can get infected with malware. To learn how to scan your machine, drop by our.

Going Forward No matter what the results of your scans were, you should check your computer regularly with NMAP to see if there is anything suspicious or simply unwanted running. Remember that unwanted services are also a potential attack surface for would-be intruders. A lean machine is a more secure machine.

Leaving vulnerable networking ports open is dangerous, even with a steller, safe OS like Linux. Having ports like this open is a great way for intruders to gain unwanted access to your Linux PC. If you’re curious about that state of ports on your Linux PC, or other network devices on your network, you may want to scan open ports and close the ones you’re not using. Scan Open Ports When it comes to port scanning, Zenmap is king. The program is by far the most well-known graphical front-end for Nmap on Linux.