Contents

Cloud IPs

Cloud IP addresses are publicly routed IP addresses that can be instantly mapped to Cloud Servers, Load Balancers or Cloud SQL instances.

Cloud IPs are “dual-stack” and each one has both both IPv4 and IPv6 addresses that are mapped together as a pair.

Cloud IPs belong to an account and can be mapped to resources on the same account. They are added to an account by “creating” them and billed by the hour until they are removed by “destroying” them.

Mapping a Cloud IP to a Cloud Server

IPv4

All cloud servers have a private IPv4 address accessible only from within the Brightbox network. Once a Cloud IP is mapped to a server, IPv4 packets to and from the Cloud IP are translated using NAT to the server’s private IPv4 address.

Outgoing IPv4 connections from the server to the Internet are translated to the first Cloud IP mapped to the server. If no Cloud IP is mapped, a shared IPv4 address is used.

Incoming and outgoing connections to and from the server’s private IPv4 (such as from other servers on the Brightbox network) are unaffected by Cloud IP mappings.

Moving a Cloud IP address will interrupt any established connections using the address.

IPv6

All cloud servers have a public /64 IPv6 network allocation. When a Cloud IP is mapped to a server, IPv6 packets to the Cloud IP IPv6 address are translated using NAT to the server’s first IPv6 address.

Outgoing IPv6 connections from the server are unaffected by Cloud IP mappings. This allows your server’s native IPv6 addresses to work exactly the same whether a Cloud IP is mapped or not.

Mapping a Cloud IP to a Load Balancer

Cloud IPs can be mapped to Load Balancers, allowing seamless transition from one server to many.

Load Balancers are inaccessible until a Cloud IP is mapped to them. Once a Cloud IP is mapped to a load balancer, packets to the Cloud IP are translated to the Load Balancers. Load Balancers do not make outgoing connections to the Internet themselves, so no outgoing translation occurs.

Mapping the first Cloud IP to a Load Balancer also triggers the Let’s Encrypt certificate generation.

IPv6

IPv6 connections to the Cloud IP address are accepted by Load Balancers and turned into a IPv4 connection to the back-end servers.

Mapping a Cloud IP to a Cloud SQL Instance

Cloud IPs can be mapped to Cloud SQL instances. SQL instances are inaccessible until a Cloud IP is mapped to them.

A note on Cloud Server interfaces

Cloud IPs are actually mapped to an interface on a server. The API accepts a server identifier as the destination and maps the IP to the first available interface.

Cloud IPs are mapped directly to load balancers as they do not have interfaces like Cloud Servers.

DNS

The first Cloud IP mapped to a Cloud Server is accessible using the DNS record public.srv-xxxxx.gb1.brightbox.com (where srv-xxxxx is the server identifier and gb1 is the region code). The name will return both A and AAAA records to give both the IPv4 and IPv6 addresses.

If no Cloud IP is mapped, the record fails to resolve (returning a NXDOMAIN).

$ host public.srv-abcde.gb1.brightbox.com
public.srv-abcde.gb1.brightbox.com has address 109.107.38.54
public.srv-abcde.gb1.brightbox.com has IPv6 address 2a02:1348:ffff:ffff::6d6b:2636

Reverse DNS

The default reverse DNS of a Cloud IP is currently of the form cip-109-107-36-145.gb1.brightbox.com. and resolves to both the IPv4 and IPv6 addresses.

Custom reverse DNS for Cloud IPs is covered in the DNS reference and in the CLI Reverse DNS Guide.

Port Translation

Port Translation can be used to change the destination port of a TCP or UDP connection coming into a Cloud IP. It can be used to emulate having multiple private IP addresses on a Cloud Server. It’s commonly used to host multiple TLS/SSL sites on the same server.

Port Translation applies only to connections coming into a Cloud IP - they do not affect outgoing connections from the Cloud Server.

See the Port Translation guide for a walk through on how to use them.

Port Translation and Firewalling

As with Cloud IP mappings, Port Translation acts on traffic before the Cloud Firewall. So, for example, if you’re translating port 443 on a Cloud IP to port 2443 on a Cloud Server, your firewall rules would need to allow port 2443.

Port Translation and Load Balancers

Cloud IPs with port translations can of course be mapped to load balancers too. You need to specify your load balancer listeners to use the translated port. So, if you’re translating port 443 to port 2443 then your load balancer needs a listener on port 2443.

Last updated: 19 Nov 2018 at 17:39 UTC

Try Brightbox risk-free with £20 free credit Sign up takes just two minutes...