Take the tour ×  I just ran nMap against my IP address and got
the following result:    • 21/tcp open ftp   • 22/tcp open ssh
• 23/tcp open telnet   • 80/tcp open http   • 443/tcp open https
• 3389/tcp open ms-term-serv  Which of these are ok to have
open, which aren't? If I close 80 and 443 will this afftect my
ability to browse the net? Will closing 21 affect my ability to
connect to FTP sites etc etc or does closing a port only affect
inbound connections?   share|improve this question add comment
3 Answers  up vote 4 down vote accepted  Assuming you scanned
from outside your network, nmap is showing you what you're
listening on. It only affects inbound. You can close the ports.
share|improve this answer Thanks for the help! –  JMK Feb 13 '12
at 20:04 add comment  I completely agree with mgjk. This traffic
is external --> internal traffic. It will not affect any
outbound connections that you make.  I just wanted to add one
thing to his information. These ports are going to come into
play if you do any