McMaster University is assigned the IPv4 address space 126.96.36.199/16, which is a range of addresses extending from 188.8.131.52 – 184.108.40.206. This address space is referred to as Public Address Space because it is globally unique and can be routed over the Internet. However, as the University network grows, our IPv4 allocation is no longer sufficient to continue using it exclusively for addressing devices on the campus network.
You many have noticed some devices using other address blocks, like 172.17.0.0/16, which is allocated to the wireless network. The formal names for those addresses are RFC1918 or private address space. Private address space can be routed internal to organizations like McMaster but not to the Internet. Devices assigned a private network address can reach the Internet using a process called Network Address Translation (NAT) which translates the private address to an external, publically routed, address in our 220.127.116.11/16 IPv4 address block (i.e. devices external to McMaster University will continue to see our familiar public address block). The process is entirely transparent to the end user. The Internet Assigned Numbers Authority (IANA) has reserved the following IPv4 address ranges for private networks.
UTS does not plan to allocate either of the first or last address blocks. The reason being they are the most common of the private address space and are used extensively on home routers and other private networks. Feel free to assign networks from 10.0.0.0/8 or 192.168.0.0/16 for your local network needs but keep in mind these networks will not be routed within our network.
Technology Services is making use of the block of addresses denoted 172.16.0.0/12 and you should avoid using this address space inside the McMaster network. When allocated, these networks will route through the campus network in exactly the same manner as 18.104.22.168/16 addresses do. That address block is currently allocated as follows:
The remaining network blocks in the 172.16.0.0/12 range will be allocated as needed. Please avoid using them for your internal projects.
Some departments may determine that they have a need for private IP address space on the local networks they use on McMaster network. Most commonly this private IP address space is needed for firewalls, virtual private networks (VPN) or computer groups. Any department that wishes to use private IP address space safely on the McMaster network should use addresses from either of these ranges:
This private network space can be used freely and will not be interfered with by UTS, however there is no guarantee you will not collide with another group that shares your network.
Those configuring a firewall or other Access Control Lists (ACL) and need to identify McMaster University networks, should configure those devices to trust these networks.
All other networks should be considered external to McMaster University.