Host Database Field: ENET-ADDDRESS, WIRELESS-ADDRESS, ADD-ENET-ADDRESS

[This document describes fields in the Princeton University Host Database. You may also view descriptions of other fields.]

An Ethernet or Wireless hardware address is a unique value built-into every device that has an Ethernet (IEEE 802.3) or Wireless (IEEE 802.11) network interface.

The hardware address uniquely identifies that network interface; no two network interfaces in the world (should) have the same hardware address. It is assigned to the device by the manufacturer.

A generic term for all these sorts of hardware addresses is 'MAC Address'; MAC stands for 'Media Access Control'.

As part of registering your device in the Host Database, you often must provide the device's hardware address(es).

If you do not know how to determine a device's Ethernet or Wireless address, see How to Determine Your Ethernet or Wireless Hardware Address.

When you register hardware addresses in the Host Database, you can enter the hardware address in Princeton's "canonical form" (i.e. 8:0:7:1a:3d:56), or a more verbose form (e.g. 0800071A3d56 or 08:00:7:1A:3D:56). The database always stores hardware addresses in Princeton's canonical form (colon-delimited, no leading 0's, lowercase letters).

Entries other than Dormnet Subscriptions

This section describes office entries (i.e. not Dormnet subscriptions).

When adding a new office entry to the Host Database

The ADDENTRY form used to add a new office entry to the Host Database contains an ENET-ADDRESS field, a WIRELESS-ADDRESS field, and several ADD-ENET-ADDRESS fields.

The ENET-ADDRESS and ADD-ENET-ADDRESS fields are used as follows:

• If your device has an Ethernet interface which is (sometimes) connected to the campus network via Ethernet wiring, then you must provide your device's Ethernet hardware address. Set the CONNECTION-MEDIA field to "Ethernet", and enter your device's Ethernet address in the ENET-ADDRESS field. Use the IP-SUBNET-OR-ADDRESS field to select the IP subnet to which this Ethernet interface is normally attached.

• Some locations are connected to the campus network via DSL (which is ultimately attached to OIT Ethernet service). If your device is connected via Ethernet wiring or Wireless to such a DSL service, then you must provide your device's hardware address. Set the CONNECTION-MEDIA field to "DSL". Enter your device's Ethernet or Wireless hardware address in the ENET-ADDRESS field. Use the IP-SUBNET-OR-ADDRESS field to select the IP subnet to which this network interface is normally attached.

• If your device is not attached via any of these sorts of networking hardware, no hardware address should be specified in the ENET-ADDRESS field, and the CONNECTION-MEDIA should be set to something other than "Ethernet" or "DSL".

• If your device has additional Ethernet interfaces, specify them in the ADD-ENET-ADDRESS fields. Otherwise, leave these fields empty.

  If you have more Ethernet addresses to add than the form has room for, add as many as you can at first, wait until you receive email saying that your ADDENTRY request has completed, then use the CHANGEENTRY form to specify the additional Ethernet addresses.

  Note that additional Ethernet addresses registered using the ADD-ENET-ADDRESS fields are not assigned IP addresses; if you also need IP addressess assigned to these interfaces, send email to hostmaster@princeton.edu ,, specifying to which IP subnet each additional interface is attached.

If your device has a Wireless interface you wish to use with OIT Wireless Service, enter the device's Wireless hardware address in the WIRELESS-ADDRESS field. There's no CONNECTION-MEDIA or IP-SUBNET-OR-ADDRESS field to go with this field on the form; the Host Database knows that the media must be "Wireless" and the correct IP subnet for the interface is "wirelessnet".

Here are some common scenarios, and how to complete the ADDENTRY form for each case:

Device with one Ethernet interface, no Wireless interface

Set the CONNECTION-MEDIA to Ethernet, set the ENET-ADDRESS to the Ethernet address, set the IP-SUBNET-OR-ADDRESS to the IP subnet to which the Ethernet interface is (usually) attached. Leave the WIRELESS-ADDRESS and ADD-ENET-ADDRESS fields blank.

Device with one Ethernet interface, one Wireless interface used with OIT Wireless Service

Set the CONNECTION-MEDIA to Ethernet, set the ENET-ADDRESS to the Ethernet address, set the IP-SUBNET-OR-ADDRESS to the IP subnet to which the Ethernet interface is (usually) attached. Set the WIRELESS-ADDRESS to the Wireless address. Leave the ADD-ENET-ADDRESS fields blank.

Device with no Ethernet interface, one Wireless interface used with OIT Wireless Service

Set the CONNECTION-MEDIA to No-Media, leave the ENET-ADDRESS field blank, and set the IP-SUBNET-OR-ADDRESS field to 'no-ip-address'. Set the WIRELESS-ADDRESS to the Wireless address. Leave the ADD-ENET-ADDRESS fields blank.

Alternatively, you can set the CONNECTION-MEDIA to Wireless, set the ENET-ADDRESS field to the Wireless address, set the IP-SUBNET-OR-ADDRESS field to 'wirelessnet'. Leave the WIRELESS-ADDRESS and the ADD-ENET-ADDRESS fields blank.

Alternatively, you can set the CONNECTION-MEDIA to Wireless, leave the ENET-ADDRESS field blank, set the IP-SUBNET-OR-ADDRESS field to 'no-ip-address'. Set the WIRELESS-ADDRESS to the Wireless address. Leave the ADD-ENET-ADDRESS fields blank.

All of these alternatives will produce the same result.

When changing an existing office entry in the Host Database

The CHANGEENTRY form is used to change an existing office entry in the Host Database.

If you need to change the device's (first) Ethernet hardware address, enter the new Ethernet hardware address in the ENET-ADDRESS field. This will cause the first hardware address in this Host Database entry to be changed to match the new address you specify. (If the entry has more than one hardware address already registered, only the first one will be changed.)

In the CHANGEENTRY form, adding, changing, and removing wireless interfaces (for use with OIT Wireless Service) is a little tricky. After you enter the name of the entry you wish to change and click the "Change Entry" button, you are presented with a page entitled "Is this the entry in question?", displaying the current Host Database entry. Instead of clicking the usual "Proceed" button at the bottom of this page, click one of the other buttons at the bottom of this page: "Add Wireless Interface", "Change Wireless Interface", or "Delete Wireless Interface". Each of these buttons will display a special form used to manipulate wireless interfaces.

If the Host Database entry has more than one hardware address, the regular CHANGEENTRY form (not the special ones used to work with wireless interfaces) will display those additional hardware addresses, but not let you change or delete them. They are all labelled "ADD-ENET-ADDRESS" regardless of whether they are actually Ethernet or Wireless. (If an IP address has been assigned to the additional hardware address, the IP address is displayed immediately after it, with the label ADD-IP-SUBNET-OR-ADDRESS; the form won't let you change or delete these either.) If you need to change or delete the additional Ethernet addresses, send email to hostmaster@princeton.edu ,. (Keep in mind that if you need to add, change, or delete Wireless hardware addresses, instead use the procedure described in the preceeding paragraph.) Finally, the form also has a few more blank ADD-ENET-ADDRESS fields, which you can use to add additional Ethernet addresses; these do not replace any existing hardware addresses.

Caveats

• Since all Ethernet and Wireless addresses must be unique, you may not register an hardware address that is already listed in another Host Database entry. Before you can register such a hardware address for your host, you'll need to correct whatever problem has caused the hardware address to currently be listed in the other Host Database entry.

• If you try to submit a registration/change request that would result in the entry having no hardware address registered (and the entry's CONNECTION-MEDIA is Ethernet, Wireless, or DSL and the ENTRY-TYPE does not end with -INACTIVE), your request will fail.

• When specifying multiple hardware addresses, be sure all the hardware addresses are for interfaces of the same device (e.g. a single computer, bridge, switch, repeater, NAT, etc). Do not specify hardware addresses corresponding to different devices in a single Host Database entry; each unique device attached to the campus network should be registered in its own Host Database entry. (In fact, registering multiple devices as if they were a single device would be a violation of OIT policy.)

Dormnet Subscriptions

As Dormnet is by definition a service that provides Ethernet-based service in dormitory rooms and apartments to currently-enrolled undergraduate and graduate students, any Host Database entry which is a Dormnet subscription must specify an Ethernet address.

A Dormnet subscription also provides the customer with the use of OIT Wireless Service in many parts of campus. That's an additional benefit, and not the primary service provided by a Dormnet subscription. Therefore, while the Host Database entry may optionally specify a Wireless hardware address as well, an Ethernet hardware address is required.

If your device has a Wireless interface but no Ethernet interface, you are permitted to use it with Dormnet, but note that this configuration is not supported by OIT. Dormnet is a wired service; it is based upon the assumption that your computer has an Ethernet interface. (In fact, an Ethernet interface is one of the minimum requirements for a computer to use Dormnet.) To use Dormnet in this unsupported way, you may register the Wireless hardware address as if it were the device's Ethernet address, and register no Wireless hardware address. The Wireless interface will be able to use OIT Wireless Service (assuming it meets that service's eligibility requirements). You will need to keep in mind that the Host Database will treat your device as if it has an Ethernet interface, and any communications from OIT may refer to your device's "Ethernet" interface since that's how it's registered.

A single Dormnet subscription provides service for a single device with one Ethernet interface and zero or one Wireless interfaces. It does not support devices with more than one Ethernet interface, or more than one Wireless interface.

A single Dormnet subscription is intended to provide service to a single device. If you have more than one device, register their hardware addresses in separate Host Database entries (e.g. multiple Dormnet subscriptions). Specifying hardware addresses that belong to different devices (e.g. two computers, or a computer and a NAT Router) in a single Dormnet subscription is a violation of OIT policy.

When a Dormnet Host Database entry is created, it contains no hardware address(es). It will continue to contain no hardware addresses while it remains unsubscribed. Any time an unsubscribed Dormnet Host Database entry is subscribed to Dormnet service, one Ethernet hardware address must be specified; one Wireless hardware may optionally be specified. If the entry is later unsubscribed from Dormnet service, the hardware address(es) are automatically removed the the Host Database entry.