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:
OIT guarantees that the following Unique Local Unicast Address (ULA) space will not be allocated by OIT for use on the campus network:
OIT will not assign IP addresses in these ranges to networks. We will not insert such IP addresses into the Host Database or any services which rely on the Host Database.
We recommend (but do not require) that departments, organizations, and individuals numbering private networks use addresses in these ranges.
If they choose to number their private networks from within the ranges above, they can be sure that the devices attached to their private networks will not become confused (now, or in the future) between their private network's IP addresses and (current or future) IP addresses on the campus network. That will be important if devices on their private networks have a way to communicate with the campus network; you would not want those private devices to become confused about whether a particular IP address is on their private network or the campus network. Such confusion could prevent these private-network-attached devices from being able to communicate with campus networks numbered using the same IP address space. Because the IP ranges above will never be used by OIT for use on the campus network, using such ranges for your private networks protects you from this pitfall.
Of course, they may choose to number their private networks in any way they wish. But if they use IP addresses from outside the ranges above, their private-network-attached devices may eventually run into the problem above. At that time, to fix the that problem, they will have to renumber their private network into the ranges above.
Regardless of how individuals choose to number a private network, they are responsible for ensuring that no private IP addresses leak from the private network onto the campus network, and that they do not announce to the campus network any routes to their private networks.