Understanding networking#

This section includes basic networking concepts that you should understand before you create a network in Rackspace Services for VMware Cloud.

Organization versus data center group networks#

Organization virtual data center (VDC) networks enable vApps to communicate with each other or with external networks outside the organization. An organization virtual data center network provides connectivity for VMs in the current VDC.

Data center group networks are a type of organization VDC network that one or more VDCs share and to which vApps can connect. A data center group network provides connectivity for VMs from all VDCs participating in the data center group.

Isolated versus routed networks#

Both isolated and routed networks are accessible only by the same organization VDC, and only VMs within this organization VDC can connect to these networks.

Isolated networks: VMs within the organization VDC can connect to and see traffic on the internal organization VDC network. The isolated network provides an organization VDC with an isolated, private network that multiple VM and vApps can connect to. This network provides no connectivity to VMs outside the organization VDC. Machines outside of the organization VDC have no connectivity to machines in the organization VDC.

Routed networks: A routed network also provides controlled access to an external network through a connected edge gateway. As a system administrator or an organization administrator, you can configure network address translation (NAT), firewall, and VPN settings to make specific VMs accessible from the external network. A routed network can be an IPv4 or an IPv6 network.

Gateway CIDR#

A gateway CIDR is a way of listing the gateway IP addresses of a network with the subnet size of that network in the following format: 192.168.0.1/24. In this example, the network gateway is 192.168.0.1, and /24 indicates that it is a 24-bit address, which you can also show as 255.255.255.0.

Static IP pools#

A static IP pool is an allocated range of IP addresses created within a network that the system dynamically assigns to devices that require an IP address.

Primary DNS#

A primary DNS server is the first point of contact for a VM, application, or device that needs to translate a human-readable hostname into an IP address. The primary DNS server contains a DNS record that has the correct IP address for the hostname. The primary DNS server could be a public DNS server such as the Google 8.8.8.8 or 8.8.4.4 server, or it could be a private internal DNS server your company uses. See your Network Administrator for help accessing your private DNS servers.

Secondary DNS#

A secondary DNS allows you to have the system back up your domain zone file onto a second set of nameservers automatically. If the first set of nameservers goes down, the request goes to the secondary nameservers, which have a zone file identical to the zone file on the primary nameservers. This could be a public DNS server like the Google 8.8.8.8 or 8.8.4.4 server, or it could be a private internal DNS server your company uses. See your Network Administrator for help accessing your private DNS servers.