Bacteriophage (2004).  Computer model of the structure of a bacteriophage showing a "chain mail" that protects this viral genome's interior. The protein structure was determined at the BioCARS beamline, operated by the University of Chicago.  Source: Argonne National Laboratory.

Public vs. private networks

What's the difference?

Computers that are connected to each other create a network.  These networks are often configured with "public" Internet Protocol (IP) addresses -- that is, the devices on the network are "visible" to devices outside the network (from the Internet or another network).  Networks can also be configured as "private" -- meaning that devices outside the network cannot "see" or communicate directly to them.

Computers on a public network have the advantage (and disadvantage) that they are completely visible to the Internet.  As such, they have no boundaries between themselves and the rest of the Internet community.  This advantage oftentimes becomes a distinct disadvantage since this visibility can lead to a computer vulnerability exploit -- a.k.a., a "hack" -- if the devices on the public network are not properly secured.

The Medical Center's private network

Most likely, your computer at work is on the Medical Center's private network.  A public/private network like the Medical Center's has the advantage that the majority of the network is "privatized," and therefore unseen directly from the Internet. 

Only a limited number of computers, such as those hosting our public Web sites, are on the public network and are therefore accessible from the Internet.  We typically set these Web servers into a protected area known as a DMZ.  By minimizing exposure to the Internet, the Medical Center's network attracts less attention for malicious network attacks.

The disadvantage of a private network is that it entails more configuration and administration to maintain usability.  At times, not being fully visible on the Internet can cause some difficulty in connecting to certain services, such as streaming audio/video, chat/instant messaging programs, or some secure Web sites.

Maintaining most computers on a private network, with only an IDP/IDS and/or Firewall visible to the public Internet helps maintain a highly secure environment for the computers on the private network, while at the same time keeping them connected to the public Internet.

How do I know if I have a public or private IP address?

You can tell by looking at it.   Click here to check your Internet Protocol (IP) addresses while on the campus network.   All of our wired and wireless network addresses are private, so the address should start with a "10" and not a "129" (the number that begins IP addresses for UM's public network).   

If it starts with a "129", give our Help Desk a call and we'll have it corrected for you.  Remember, your computer is more secure with a private IP address.

If you are reading this page from an off-campus location, you can check your IP address at web sites like this one.  The IP address will be one assigned to your Internet Service Provider.

If you have questions about how we administer the Medical campus private network, contact our Network Engineering group.   To learn more about networks generally, use the materials in our Learn about series.