0

I was unable to log back into some EC2 instances using my domain administrator account after changing their type from T2 to T3.

I was able to log into most servers using their root admin credentials, but it looked as though the DNS server addresses in my IPv4 settings (pointing to my Simple AD) were reset back to "Obtain DNS server address automatically". I changed back to using my simple AD and the servers began working normally again. enter image description here

However one server is currently unreachable by domain or root credentials. It simply returns this not entirely helpful error:

"This computer can't connect to the remote computer. Try connecting again. If the problem persists, contact the owner of the remote computer or your network administrator."

  • I've made sure my security group allows RDP access to my IP (it's the same on the other EC2 instances).
  • Created and launched an image of the EC2 instance - same error.
  • I also tried detaching the root volume from the instance and attaching it as the root for another instance- no luck.

Is there anything else I can try?

Aaron
  • 115
  • 1
  • 9
  • Use SSM Session Manager to connect to the instance. You do not need RDP running, no ports need be open, etc. Very cool management tool for connecting to instances (Linux & Windows). https://aws.amazon.com/blogs/aws/new-session-manager/ – John Hanley Sep 19 '18 at 17:32
  • You can configure a [DHCP Options Set](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_DHCP_Options.html) so that VPC tells your instances which DNS to use. This way, each instance can use "Obtain DNS automatically", while having them point to your Simple AD. – John Rotenstein Sep 19 '18 at 19:51

0 Answers0