I work on WindowsXP IE8
I tried, without success, to enter the library site of a German University.
After contacting them by e-mail they advised to open port 8080 in order to receive their catalog on my browser.
Please explain what and how can this port be open and if are there any risks to do it.
Thanks

Normally you open ports in your firewall, and/or your router. So you need to determine what you have first. Then you plug that information into Google. For example, open ports in windows xp firewall or open ports in linksys router

Foundations: What Is a Port? Security Basics | WatchGuard

If me, I would open the port only when I needed it, then close it when done.