Working with Networks in Horizon

Create a Network

  1. Network
  • You will need a network that Virtual Machines can use.

  • If auto_allocated_network exists from Exosphere, you may wish to use that one and can skip ahead.

  • In the left menus, click on ProjectNetworkNetwork Topology+Create Network

  1. Network name
  • Enter a network name, for example, <username>_net.

  • After giving it a descriptive name, press the blue NEXT button.

  1. Subnet
  • Enter a subnet name, e.g. <username>_subnet, and
    a network address, e.g., and
    a gateway address, e.g.

    • This should be a non-routable subnet.
    • You can use -, -, -
  • If you’re not sure what to choose, you can go with → this will give you 255 available addresses in the domain.

  • If you choose you can then set the gateway address to be

  • After giving it a descriptive name, press the blue NEXT button.

  1. Create
  • Click Create to create the new network.

    Do NOT uncheck the Enable DHCP box unless you are familiar with setting the advanced features of OpenStack networks, subnets, and routers.

  1. Router
  • Jetstream2 Policy defaults to router quota = 1.
    If you already have the auto_allocated_network and have not requested a quota increase, the button +Create Router may be greyed out.

  • Click on +Create Router.

  1. Router name
  • Enter a router name, for example, <username>_router.
  • Under the External Network dropdown, select public, then click Create Router
  • After giving it a descriptive name, press the blue NEXT button.

  1. Connect Network to Router
  • You’ll need to connect your private network to the router.
    Make sure you’re in Graph mode (vs Topology mode). Your screen should look like the top image on the right.

    • If it looks like it’s in Topology mode, click the Graph tab under the Network Topology page heading to put it into Graph mode
  • Click on the router you just created (or auto_allocated_router ),
    then +Add Interface.


If auto_allocated_network is present, you can simply use auto_allocated_network without all these steps. You only need to connect to the auto_allocated_router if you need a separate CIDR block for your VMs.

  1. Select subnet
  • Select the subnet you previously created from the dropdown list.

  • Click Submit

  1. The network should now be connected to the new router. The end result will look similar to the diagram.