Score:0

Connectivity between two EC2 instances does not work

it flag

I try to ping or ssh between these instances (A to B), neither work, both time out.

  • Instance A (i-0e332d1880c8f93ae) - CentOS
  • Instance B(i-0a1e4a76358059ba3) - Debian

They share VPC, and the security groups and Network ACL are properly configured. The AWS connectivity analysis tool confirmed this for both ICMP and ssh.

(Image: https://i.stack.imgur.com/5VZo9.png , no enough reputation)

There is not any firewall in the instance B.

Both are accessible from their public IPs, but can't communicate each other.

Any idea why ?

sa flag
I don't know this connectivity analysis tool. I notice there's at the top and bottom are this very specific source and destination IP. Do the security rules allow traffic to go *both ways*?
Jean-François Kener avatar
it flag
The analysis tool appears to be a new addition in Amazon. Regarding the security rules, yes, I allowed SSH and ICMP as inbound/outbound rules in both directions, but neither work. I tried allowing both directly the private IP addresses, and the security groups, in the rules.
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