What could prevent one Amazon EC2 instance from pinging another instance's Private IP?

Posted by ks78 on Server Fault See other posts from Server Fault or by ks78
Published on 2011-02-06T07:15:19Z Indexed on 2011/02/06 7:27 UTC
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Filed under:

networking

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firewall

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amazon-ec2

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ip

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ip-address

I have multiple Amazon EC2 instances which need to communicate using private IPs. However, so far I've been unable to ping one instance's private IP from another instance.

I can ping external addresses, such as their Elastic IPs and other sites (yahoo, google, etc), so it seems there's nothing wrong with the instances' network configuration.

Also, they are all in the same zone, so that shouldn't be an issue.

Does anyone have any idea what I could be doing wrong? Could this related to the Security Group settings?

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