Nobus FCS and Nobus Data-center support only the IPv4 addressing protocol. IPv6 addressing protocol is not supported for now. By default, Nobus FCS and Nobus Data-center use the IPv4 addressing protocol. You must specify an IPv4 CIDR block (a range of private IPv4 addresses) when you create a Data-center. IPv4 addresses can be reached from the Internet.
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A private IPv4 address is an IP address that cannot be reached over the Internet. The private IPv4 addresses are suitable for communication between instances in the same Data-center and are allocated to instances via DHCP. see RFC 1918 for more information about the standards and specifications of private IPv4 addresses,.
You can create a Data-center with a publicly routable CIDR block that falls outside of the private IPv4 address ranges specified in RFC 1918. However, for the purposes of this documentation, we refer to private IPv4 addresses (or 'private IP addresses') as the IP addresses that are within the IPv4 CIDR range of your Data-center.
When you launch an instance, we allocate a primary private IPv4 address for the instance.
An instance receives a primary private IP address from the IPv4 address range of the subnet. If you don't specify a primary private IP address when you launch the instance, we select an available IP address in the subnet's IPv4 range for you. Each instance has a default network interface (eth0) that is assigned the primary private IPv4 address. You can also specify additional private IPv4 addresses which can be reassigned from one instance to another.
A private IPv4 address, regardless of whether it is a primary or secondary address, remains associated with the network interface when the instance is stopped and started, or hibernated and started, and is released when the instance is deleted.
A public IP address is an IP address that's reachable from the Internet. These public addresses are suitable for communication between your instances and the Internet.
Each instance that receives a public IP address is also given an external DNS hostname;
for example, FCS-203-0-113-25.compute-1.NobusNCS.com. We resolve an external DNS
hostname to the public IP address of the instance from outside its Data-center, and to
the private IPv4 address of the instance from inside its Data-center.
The public IP address is mapped to the primary private IP address through network address translation (NAT).
For more information, see
RFC 1631: The IP Network Address Translator (NAT).
When you launch an instance in a default Data-center, we assign it a public IP address by default. When you launch an instance into a nondefault Data-center, the subnet has an attribute that determines whether instances launched into that subnet receive a public IP address from the public IPv4 address pool. By default, we don't assign a public IP address to instances launched in a nondefault subnet.
You can control whether your instance receives a public IP address as follows:
Modifying the public IP addressing attribute of your subnet.
See Nobus flexible network interface (FNI) for information.
Enabling or disabling the public IP addressing feature during launch, which overrides the subnet's public IP addressing attribute. For more information, see Assigning a public IPv4 address during instance launch.
A public IP address is assigned to your instance from Nobus's pool of public IPv4 addresses, and is not associated with your NCS account. When a public IP address is disassociated from your instance, it is released back into the public IPv4 address pool, and you cannot reuse it.
You cannot manually associate or disassociate a public IP address from your instance. Instead, in certain cases, we release the public IP address from your instance, or assign it a new one:
We release your instance's public IP address when it is stopped, hibernated, or deleted. Your stopped or hibernated instance receives a new public IP address when it is started.
We release your instance's public IP address when you associate a Floating IP address with it. When you disassociate the Floating IP address from your instance, it receives a new public IP address.
If the public IP address of your instance in a Data-center has been released, it will not receive a new one if there is more than one network interface attached to your instance.
If your instance's public IP address is released while it has a secondary private IP address that is associated with a Floating IP address, the instance does not receive a new public IP address.
If you require a persistent public IP address that can be associated to and from instances as you require, use a Floating IP address instead.
If you use dynamic DNS to map an existing DNS name to a new instance's public IP address, it might take up to 48 hours for the IP address to propagate through the Internet. As a result, new instances might not receive traffic while deleted instances continue to receive requests. To solve this problem, use a Floating IP address. You can allocate your own Floating IP address, and associate it with your instance. For more information, see Floating IP addresses.
a Floating IP address is a public IPv4 address that you can allocate to your account. You can associate it to and disassociate it from instances as you require. It's allocated to your account until you choose to release it. For more information about Floating IP addresses and how to use them, see Floating IP addresses.
Nobus provides a DNS server that resolves Nobus-provided IPv4 DNS hostnames to IPv4 addresses.
You can assign a public IPv4 address to your instance when you launch it. You can view the IPv4 addresses for your instance in the console through either the Instances page or the Network Interfaces page.
You can use the Nobus FCS console to view the private IPv4 addresses, public IPv4 addresses, and Floating IP addresses of your instances. You can also determine the public IPv4 and private IPv4 addresses of your instance from within your instance by using instance metadata.
The public IPv4 address is displayed as a property of the network interface in the
console, but it's mapped to the primary private IPv4 address through NAT. Therefore,
if you inspect the properties of your network interface on your instance, for
example, through ifconfig (Linux) or ipconfig (Windows), the public
IPv4 address is not displayed. To determine your instance's public IPv4 address
from an instance, use instance metadata.
To view the IPv4 addresses for an instance using the console
Open the Nobus FCS console at https://cloud.nobus.io/project/ .
Goto Project, choose Instances and select your instance.
The following information is available on the Networking tab:
Public IPv4 address — The public IPv4 address. If you associated a Floating IP address with the instance or the primary network interface, this is the Floating IP address.
Public IPv4 DNS — The external DNS hostname.
Private IPv4 addresses — The private IPv4 address.
Private IPv4 DNS — The internal DNS hostname.
Secondary private IPv4 addresses — Any secondary private IPv4 addresses.
Floating IP addresses — Any associated Floating IP addresses.
Each subnet has an attribute that determines whether instances launched into that subnet are assigned a public IP address. By default, nondefault subnets have this attribute set to false, and default subnets have this attribute set to true. When you launch an instance, a public IPv4 addressing feature is also available for you to control whether your instance is assigned a public IPv4 address; you can override the default behavior of the subnet's IP addressing attribute. The public IPv4 address is assigned from Nobus's pool of public IPv4 addresses, and is assigned to the network interface with the index of eth0. This depends on current conditions at the time you launch your instance.
Note
You can't manually disassociate the public IP address from your instance after launch. Instead, it's automatically released in certain cases, after which you cannot reuse it. For more information, see Public IPv4 addresses and external DNS hostnames. If you require a persistent public IP address that you can associate or disassociate at will, assign a Floating IP address to the instance after launch instead. For more information, see Floating IP addresses.
You cannot auto-assign a public IP address if you specify more than one network interface. Additionally, you cannot override the subnet setting using the auto-assign public IP feature if you specify an existing network interface for eth0.
The public IP addressing feature is only available during launch. However, whether you assign a public IP address to your instance during launch or not, you can associate a Floating IP address with your instance after it's launched. For more information, see Floating IP addresses.