Is it dangerous to open ports on a router/firewall?

[pstj]

Hi!
Is it dangerous to open ports on a firewall (a router) to allow connection for various applications (icq, ftp, file sharing, etc.)? Does it make the computer/network *significantly* more vulnerable to hacking?

Thanks!

[Confused]

Yes. Probably best is to only open the port when needed by the application and close the port after you are finished.
Chas

[mairving]

Opening a port makes you a target for sure. Port scans are run on the Internet all the time. If they find an open port, you could get hacked or at least they will try.

[morriswindgate]

You can get a nice little freeware program at the link below called Active Ports that allows you to see what port is being used and by what program, close or open ports, and restrict port usage.

http://www.ntutility.com/freeware.html

[pstj]

Thank you all for the help! :)