ELB Listeners Part 1

• Before you start using Elastic Load Balancing, you must configure one or more listeners for your ELB.

• A listener is a process that checks for connection requests.

• It is configured with a protocol and a port for front-end (client to load balancer) connections, and a protocol and a port for back-end (load balancer to back-end instance) connections.

• Elastic Load Balancing supports the following protocols:

  • HTTP

  • HTTPS (secure HTTP)

  • TCP

  • SSL (secure TCP)

• The HTTPS protocol uses the SSL protocol to establish secure connections over the HTTP layer.

• You can also use the SSL protocol to establish secure connections over the TCP layer.

• If the front-end connection uses TCP or SSL, then your back-end connections can use either TCP or SSL.

• If the front-end connection uses HTTP or HTTPS, then your back-end connections can use either HTTP or HTTPS.

Create an HTTPS listener for your ALB

• You can create an HTTPS listener, which uses encrypted connections (also known as SSL offload).

• This feature enables traffic encryption between your load balancer and the clients that initiate SSL or TLS sessions.

• To use an HTTPS listener, you must deploy at least one SSL/TLS server certificate on your load balancer.

• The load balancer uses a server certificate to terminate the front-end connection and then decrypt requests from clients before sending them to the targets.

• The load balancer requires X.509 certificates (SSL/TLS server certificates).

• Certificates are a digital form of identification issued by a certificate authority (CA).