Keeps "SSH timeout" error in our AWS instance- how do i diagnose?

Question

I am befuddled by this error. We keep failing to SSH into our AWS instance, whether it is is deployment or via console. I have tried rebooting a few times, but it does not seem to be helping.

Here are a couple of error messages i keep getting.

connection failed for: HOST.NAME.amazonaws.com (Errno::ETIMEDOUT: Operation timed out - connect(2))

111.222.333.444: ssh connection failed at 2010-07-02 03:39:37

I also SSHed in when it was up, and monitored "top" when ssh times out. looking at the memory logs, it does not look like any program was hogging

Answer 1

To help diagnosis add this to your client's ssh_config:

# Check every 60s
ServerAliveInterval 60
# Timeout after 40m
ServerAliveCountMax 40

Answer 2

Add ssh to your security group e.g. via aws console https://console.aws.amazon.com/ec2/home