Yes.
To connect to a Library Server, Media Center needs to be able to reach that Library Server's
Web Service via the TCP Port defined in
Tools > Options > Media Network > Advanced > TCP Port, and have the username and password to authenticate to it. This port is 52199 by default.
So, there are two ways you can make this work from across the Internet:
1.
Port Forwarding: You can forward the port through your home router's firewall to the Server. How you do this varies dramatically depending on your particular network setup, but there are a ton of resources online about
Port Forwarding. Here are a couple simple guides:
*
http://www.wikihow.com/Set-Up-Port-Forwarding-on-a-Router*
http://www.noip.com/support/knowledgebase/general-port-forwarding-guide/2.
VPN: Instead, you could set up a VPN for your friend, so they can connect to your network as though they are on the local LAN.
This is
much safer than using Port Forwarding. Please note that MCWS (the web service that backs Media Network functionality in MC) does not currently use TLS encryption (like a HTTPS website). This means anyone monitoring your network traffic with a packet capture (or that of your friend connecting to your server) could sniff the username and password and all other connection details needed out of the traffic, and use this information to connect to your Library Server themselves, and now
they can create and delete playlists, tag files, and delete things at will. Port forwarding also directly exposes the Media Center processes to the Internet (and relies on JRiver to never have any buffer overflow vulnerabilities in their web service).
Creating a VPN, though, is a bit more complex than just forwarding a port. Once done, however, it will provide additional functionality to your remote user (as they can also have direct access to any filesystem shares you've created at home). Again, it is a bit out of scope for Interact to give you detailed assistance on creating a VPN at home, but here's a decent resource with some options:
http://www.howtogeek.com/221001/how-to-set-up-your-own-home-vpn-server/