Not able to login to EC2 instance through putty.

Question

We were not able to login into my EC2 instance through putty and giving error "Network error: Software caused connection abort". We saw on AWS console that EC2 instance was running but still not able to login and also saw that CPU utilization for some period is showing nothing and suddenly showed utilization after few minutes.

After that we restarted the EC2 instance and we were able to connect it . Can anyone help me to know why this has happened?

After that we restarted the EC2 instance and we were able to connect it .
Can anyone help me to know why this has happened?

Answer

Hey there! Warm greetings.

You have mentioned that you cannot connect to your instance via PuTTY. Which is giving you an error “Network error: Software caused connection abort”.

With regards to the error experienced, this error is usually experienced when using PuTTY to connect to the instance, and occurs when the session is left idle for some time, which causes PuTTY to break the connection. This can be resolved by setting a keepalive by navigating to "Connection" -> "Seconds between keepalives", and setting a value greater than 0. For more information on the error I have added a reference document [1].

Further more the CPU utilisation could have showed nothing and after a few minutes showed that it was being utilised because the instance was in a stop state. When it comes to CloudWatch metrics it takes about 5 minutes before it is populated, unless you have detailed monitoring configured which takes about 1 minute to populate the CloudWatch metrics [2].

References:

[1] https://superuser.com/questions/294824/putty-network-error-software-caused-connection-abort

[2] https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-cloudwatch-new.html

Not able to login to EC2 instance through putty.

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