OIT Visitor IP Service provides Internet service to devices when they are attached via Ethernet to the guestnet network. The guestnet network is intended to be available only in the guest rooms of Palmer House. (Palmer House is a University guest house.)
The following procedures apply to all computers attached to the campus network, but are of special importance for visitor devices:
E.g. if your computer is in any of these modes, then before attaching a Ethernet cable, first wake up your computer, shut it down entirely, then attach the cable, and finally start up your computer.
By shutting down entirely, you are less likely to make the mistake of later re-attaching your computer to a network cable while the computer is powered-on or sleeping. (And you'll also avoid needing to wake up a sleeping computer just so you can power it down before re-attaching it to networking wiring.)
The following items are specific to Visitor IP Service:
Visitors can help us to minimize such problems by ensuring that the computers they bring to campus have all current updates installed, are properly secured against intrusion, and have current antiviral software. And in particular, visitors should not attach any DHCP servers to the network.
When a device using Visitor IP Service is the source of a problem, OIT's response is typically to track down the Ethernet port to which the device is (or was) attached, turn off the Ethernet port, and notify Palmer House management. Once Palmer House management advises us that the device causing the problem has been disconnected (or fixed), OIT re-enables the Ethernet port.
To use OIT Visitor IP Service, your device must meet the following technical requirements:
This lease has a short duration, typically 2-12 hours. While your computer remains attached to this network and continues to use IP, it periodically contacts OIT's DHCP servers to renew this lease. If your computer is restarted (or allows the lease to expire for some other reason), the DHCP servers may assign to it a different Visitor IP address and Internet hostname.
A list of the clients currently assigned Visitor IP addresses appears in Current Visitor IP Address Assignments.
In particular, Princeton University blocks certain kinds of traffic at our Internet connection, typically for security reasons. Software that relies on blocked traffic will not be able to communicate with other devices on the Internet.
For example, some University services restrict access to devices within the princeton.edu DNS domain. Devices using Visitor IP Service are in the princeton.org DNS domain. This is intentional, to underscore that they are not truly Princeton University devices.
Some University services restrict access to devices within certain IP address ranges, on the assumption that these IP addresses are associated with the Princeton University campus. (This assumption is not entirely accurate, but is mostly correct.) All of guestnet uses a different IP address range, in part to help underscore that this is not the same as any other campus network. This way, operators of services restricted by IP address will not accidentally find themselves providing service to guestnet; these operators will need to make a deliberate decision to reconfigure their services if they wish to extend service to guestnet. See IP Network Ranges at Princeton University.
Some client DHCP implementations or configurations may have problems that are not apparent when they are only used on their home networks; these clients then encounter problems when trying to use OIT Visitor IP Service. When we discover a DHCP client that function in such a way as to interfere with OIT Visitor IP Service, we may declare the device Ineligible for OIT Visitor IP Service. A list of devices that have been declared ineligible appears in Devices Blocked from Visitor IP Service.
The most common DHCP client malfunctions of this sort include ignoring DHCP lease times (continuing to use an IP address after its lease has expired), or running multiple DHCP clients on a single interface (hardware address).
For example, if you subscribe to a commercial network service that only accepts your connection from your own corporate or home network (based upon IP address or Internet hostname), you may not be able to connect while you are using OIT Visitor IP Service. The same may be true if you use licensed software that is customized to only run if your computer is attached to your own corporate or home network.
Currently our convention for the Internet hostnames associated with Visitor IP addresses is: visitor-ip-LETTER-NUMBER.princeton.org, where LETTER denotes which OIT DHCP server owns the Visitor IP address. This convention may change in the future.
If you have questions or need assistance with any of the procedures in this document, please contact the OIT Support and Operations Center.