open ports in ubuntu 13.10

Question

Ubuntu comes with no open ports. Mine is a fresh install with only skype xbmc and wine added. I installed GUFW and set it to ON. When I do sudo netstat -tulpn | grep LISTEN I got:

tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      610/cupsd       
tcp        0      0 0.0.0.0:25              0.0.0.0:*               LISTEN      27832/master    
tcp        0      0 127.0.1.1:53            0.0.0.0:*               LISTEN      1201/dnsmasq    
tcp6       0      0 ::1:631                 :::*                    LISTEN      610/cupsd       
tcp6       0      0 :::25                   :::*                    LISTEN      27832/master    

Is this normal? Should I worry? Any and every answer is appreciated.

Answer 1

631 is internet printing protocol
25 is smtp
53 is for local dns

as the addresses services are listening to is 127.0.0.1 no external requests will be handled. so the only thing accessable from outside is 25 for smtp. which is used to deliver e-mail to your server

Answer 2

Nothing to be worried about your results are normal .

Answer 3

smtp (port 25) is used to push out e-mail to a receiving pop- or imap-server. Always try to use the smtp of your isp first. If you're only using your PC for desktop usage I would strongly recommend to uninstall exim4. If you don't use it and keep it installed, make sure you also block outgoing connections in your firewall. Most people don't want their desktop turned into a spambot ...