OIT Visitor IP Service provides Internet service to devices not registered in the Princeton University Host Database when they are attached via Ethernet to the guestnet network in the guest rooms of Palmer House. (Palmer House is a University guest house.)
Devices registered in the Princeton University Host Database do not receive Visitor IP (VIP) Service. Instead, they ordinarily receive OIT Mobile IP Service when visiting guestnet.
Visitor IP Service should not be confused with Temporary Visitor Wireless Network Access, a different service that provides short-term Internet connectivity to wireless devices brought by visitors to select portions of the University campus.
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.
Visitors to the main campus may obtain short-term Internet connectivity for wireless devices in a number of locations by using Temporary Visitor Wireless Network Access(TVWNA).
Campus visitors who need network connectivity that TVWNA does not provide (e.g. wired service, or longer-term service) should discuss their needs with the University member or department with whom they are visiting. University members can register the visitor's device in the Princeton University Host Database; the University member will have to take responsibility for the device's behavior on the network, and provide an account number to bill for the network service.
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. This includes, for example, NetBIOS-over-IP, SNMP, RPC portmapper, and NFS. Software that relies on blocked traffic will not be able to communicate with other devices on the Internet. (The most common software of this sort include Windows file and printer sharing, and some Microsoft email applications.)
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. (If your device is a Princeton University device, register it in the Princeton University Host Database; that way it will receive OIT Mobile IP Service when visiting guestnet, and thus will have a princeton.edu DNS name.)
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 (both Visitor IP Service and OIT Mobile IP Service operating on that network) 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.
In particular, the current DHCP specification has evolved rapidly in recent years, so older client software may not work right. If the DHCP specification changes in the future, you may need to update the DHCP software on your computer to continue to use OIT Visitor IP service.
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.