The following globally-routable IP network ranges are presently part of the Princeton University campus network:
The following non-globally-routable IP network ranges are presently part of the Princeton University campus network:
Note that the campus network may include some devices belonging to organizations that are simply affiliated in some way with Princeton University. An IP address that falls into any of the ranges above is not guaranteed to be associated with a device owned or operated by Princeton University; it may be a device operated by an independant organization that is simply affiliated in some way with the University. And in some cases, the device may have absolutely no affliation with the University at all.
Conversely, there may be devices owned or managed by Princeton University which are attached to the Internet outside the campus network; such devices may have IP addresses outside the ranges above. Therefore, an IP address that falls outside the above ranges is not guaranteed to be unaffiliated with the University.
OIT guarantees that the following parts of the RFC 1918 IP address space will not be allocated by OIT for use on the campus network:
Departments, organizations, and individuals numbering private networks may wish to use addresses in these ranges to avoid confusion.
Of course, they may choose to number their private networks in any way they wish, given that they are responsible for ensuring that no private IP addresses leak from their network onto the campus network, and that they do not announce to the campus network any routes to their private networks. However, if they choose to number their private networks from within the ranges above, they can be sure that there will be no confusion on their private network between their private network's IP addresses and the IP addresses on campus. That may be important if devices on their private networks have a way to communicate with the campus network, so you would not want those private devices to become confused about whether an IP address was on their private network or the campus network.