Page History

Networks created within the openstack platforms are not routed trough through NTNU, thus in theory it is not important which subnet is selected. It might however be a problem if your virtual machine needs to contact external resources and you have provision your virtual machines within the same address range that is currently being use elsewhere, causing your local address range to overlap with the address range of another network. Because of this, it is common practice to use the address ranges specified in the RFC1918 (a.k.a IPv4 Private Address Space):

• 10.0.0.0/8
• 172.16.0.0/12
• 192.168.0.0/16
  
  • tl;dr - use a subnet from this range to avoid any weird issues → 192.168.N.0/24 where N is a number from 0 and 255.

RFC1918 within NTNU

NTNU is however using the following subnets within the RFC1918 range, therefore their use should be avoided:

• 10.0.0.0/8 - Large pieces of this range is already in use; and this block is likely to be used in new subnets within NTNU as well. It is thus recommended not to use this block at all:

  Broadcast	10.255.255.255
  HostMin	10.0.0.1
  HostMax	10.255.255.254
  Max amount of hosts	16777214

  172.16.0.0/16 - Used as floatingThe general purpose floatin-IP's in skyhigh.hig.no; free in other clouds

  Broadcast	172.16.255.255
  HostMin	172.16.0.1
  HostMax	172.16.255.254
  Max amount of hosts	65534

• 172.17.0.0/16 - Used within NTNU in Gjøvik, and is thus not recommended to use it in openstack networks.

  Broadcast	172.17.255.255
  HostMin	172.17.0.1
  HostMax	172.17.255.254
  Max amount of hosts	65534

• assigned in openstack is also from this range, and it can thus involve a bit of confusion if both the vm's IP and the floating-ip looks the same. It is thus recommended not to use this block at all.

• 172.17.0.0/16192.168.0.0 - The following twelve subnets are partly used in NTNU Ålesund, the rest are free:
  

• 192.168.10.0/24

  Broadcast	192.168.10.255
  HostMin	192.168.10.1
  HostMax	192.168.10.254
  Max amount of hosts	254

• 192.168.30.0/24
• 192.168.50.0/24
• 192.168.90.0/24
• 192.168.110.0/24
• 192.168.114.0/24
• 192.168.201.0/24
• 192.168.212.0/24
• 192.168.221.0/24
• 192.168.222.0/24
• 192.168.223.0/24
192.168.224.0/24