Managed Load Balancer Hostnames and IP addresses

Load Balancer is designed such that its IP addresses should not change. However, the IP is not fixed and may change in certain circumstances. Therefore, we recommend always using the Load Balancer hostname instead of the IP address when accessing services behind a Load Balancer.

Addresses on private networks

On each SDN Private Network attached to the load balancer, every load balancer node holds two addresses. The API lists them under each node's networks:

• The address marked "listen": true is the load balancer's private frontend address on that network.
• The address marked "listen": false is the node's own address. Your backend servers see it as the source of every health check and every forwarded request.

A plan with two nodes, such as Production Small, therefore holds four addresses on each private network. The addresses are assigned when the load balancer is created and are known once it is running. If your backend servers filter incoming traffic, for example with the SDN Firewall, allow the "listen": false addresses on the backend port.

Until the health checks of a backend's members pass, a frontend that uses that backend answers with HTTP 503.