RFC1918 Address Space Usage

RFC1918 describes a set of network ranges set aside for so-called "private" use. This document provides important information for IT Officers who may be considering using these addresses on their network.

Hostmaster at IT Services follows a policy of always providing public IP addresses to units as outlined on the IPv4 Address Allocation Policy page. The University was in a fortunate position in having considerable public IP space, but the remainder must now be carefully managed. For example devices which have no need to contact the Internet or be accessible to other systems in Oxford, such as printers and network switches, may be allocated RFC1918 addresses.

Where there is no requirement to use your public IP addresses allocated by Hostmaster at IT Services, you may be able to make use of these networks. For example, some devices which do not (and should not) need Internet access, such as IP CCTV cameras, may be good candidates for moving onto RFC1918.

The RFC1918 ranges are:

  • 10.0.0.0 - 10.255.255.255 (10/8 prefix)
  • 172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
  • 192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

Some of these address ranges are reserved for specific use within the Univeristy. The available RFC1918 subnets for use within the college/Departament internal networks are listed on the IPv4 Address Allocation Policy page. This will eventually allow us to allocate and hence route some RFC1918 addresses within the Odin network, giving greater scope for (re-)using the remaining limited public IP address space.

 

 

Written by IT Services. Latest revision 20 January 2017