devops-exercises/exercises/aws/solutions/no_application.md

No Application :'(

Objectives

Explain what might be possible reasons for the following issues:

1. Getting "time out" when trying to reach an application running on EC2 instance
2. Getting "connection refused" error

Solution

1. 'Time out' Can be due to one of the following:

• Security group doesn't allow access
• No host (yes, I know. Not the first thing to check and yet...)
• Operating system firewall blocking traffic

2. 'Connection refused' can happen due to one of the following:

• Application didn't launch properly or has some issue (doesn't listens on the designated port)
• Firewall replied with a reject instead of dropping the packets