Dormnet Backbone IP Network Change

CIT Network Systems
July 9, 1996

The IP subnet mask ("netmask") for the Dormnet backbone network has been changed. This change is necessary due to the growth in Dormnet service to include the Graduate College, and to include service during the Summer recess.

Customers using supported Mac & PC platforms configured as recommended by CIT (i.e. configured using BootP or DHCP) do not need to do anything to reconfigure, and need read no further.

Who is Affected?

The change only affects devices attached to the Dormnet backbone network.

You can determine if a device is on that network by checking its assigned IP address; if it begins with 140.180.[128-191], it is on the Dormnet backbone network.

If you don't know your device's IP address, you may assume that it is on the Dormnet backbone network if it's located in a dormitory room, eating club, or any office within a dormitory building or residential college. Otherwise, you can assume your device is not on the Dormnet backbone, and your device is not affected.

What Devices Use BootP or DHCP?

Most Mac and PC workstations are configured to use BootP or DHCP. If your device uses BootP or DHCP and is on the Dormnet backbone, it configures itself automatically when it is started.

Devices that are typically configured to use BootP or DHCP include:

• Macs and PCs originally purchased from CIT as Dormnet-Ready or Office-Ready

• Macs and PCs on which CIT staff have previously installed Basic System-Level Network Connection Software

• Macs and PCs on which you have self-installed Basic System-Level Network Connection Software yourself by following published CIT instructions.

• X Terminals

Reconfiguring Other Devices

Some devices are not configured to use BootP/DHCP, or are unable to do so. Instead they have been manually configured with IP network information. If the device is on the Dormnet backbone, you will need to reconfigure it manually.

These devices typically include:

• UNIX workstations, such as Suns, Irises, etc. This also includes any Macs or PCs running a version of UNIX (e.g. Linux).

• Macs or PCs you have configured yourself, to not use BootP or DHCP (i.e. not configured as recommended by CIT)

• Any Mac or PC that was using BootP or DHCP, that you later reconfigured to not use BootP or DHCP (not recommended by CIT)

• Other devices that speak IP but do not support BootP or DHCP.

In these cases, you will need to reconfigure your device. If your device is a supported Mac or PC platform, we recommend you reconfigure its TCP/IP software to rely on BootP or DCHP, by following instructions in existing CIT documentation. For other platforms, you will need to determine how you configure the IP subnet mask and change it from 255.255.224.0 to 255.255.192.0.

There is no urgency in reconfiguring your device. It will continue to function with the old configuration. We recommend that you reconfigure your device by the Fall.