AWS ELB getting lots of 404 errors from Fastly health check

Question

In my logs for my Elastic Beanstalk App I keep seeing "GET /aetn-heartbeat.html HTTP/1.1" 404 158 "-" "Varnish/2.1+fastly (healthcheck)"

The load balancer is working fine, but the health of my ELB is constantly showing degraded health because of these 404 errors and it's a bit confusing. My question is: Do I ignore these 404s? Figure out a way to block these requests? Or is there a real issue that should be addressed?

Answer 1

AWS is open cloud environment. By which I mean you can get all sort of requests from all around the world, Maybe the IP address (or even the DNS name) assigned to your AWS EB environment was hard coded in someones application around the world. Or even worse someone is trying to hack in. That's the only reason AWS promotes its shared responsibility model. You can get all sort of requests from anywhere around the world. A better way to block them is to use AWS WAF and allow only the urls you want to pass through. You can find 2 common ways of using AWS WAF with EB

1. Associate the AWS WAF with ALB
2. Use AWS WAF with AWS cloudfront and ELB

Secondly you can also handle this on code level and do not send 404 if AWS is hard to implement. But I'll recommend using AWS WAF