I was playing around with nmap and scanned my own linux machine for open ports. Since I was running an apache2 server it displayed that port 80 is open.
My question is what are the difference between these kind of ports and all the other ports my machine is using (for example while surfing on the internet). I can't really see the difference and I would like to know why nmap only showed that port 80 is open and ignored all the other ones.
Just think ports as gates that open outside. Only thing that makes difference between gates is what is inside? Technicaly, which service is running behind the port? You can run any service on any port. You do not have to run HTTP service on the port number 80. You can set it any port if you want.
Outputs you see after nmap scan is totaly upto which parameters you have given to nmap query. You can give more parameters to get more and detailed results.
Even if you give detailed search query and nmap gives you only the port 80, it does not mean it's wrong. Only port 80 can be open, it's not an unusual situation. All other ports can be close or other port can be outside of your scan range or you may not scan all other ports.
