- Newest
- Most votes
- Most comments
Did you try these?
https://aws.amazon.com/tr/premiumsupport/knowledge-center/ec2-instance-boot-issues/
You can try setting new SSH key pair once and try to login again. Please refer the below link for generating and setting up the new key pair for the instance: https://aws.amazon.com/premiumsupport/knowledge-center/user-data-replace-key-pair-ec2/
Hello,
One possible reason for this issue could be that the DNS record you added is somehow interfering with your SSH connection. To verify this, you can try connecting using the instance's IP address rather than the DNS record. Additionally, you can use the "dig" or "nslookup" commands to test if DNS resolution is functioning correctly.
For example:
- dig domain.com
- nslookup domain.com
If you are still unable to connect, I recommend that you check the network settings for your instance, specifically the Network Access Control Lists [2] and security groups [1] to verify if All ICMP protocol [3] is part of the rules with the correct source configured. Depending on the configurations these rules can block incoming/outgoing traffic and prevent successful communication between your instance and the internet. Also check that the instance has a public IP assigned. This should be the IP that DNS resolves to. And the route table has a default route 0.0.0.0/0 pointing to an IGW [6]. VPC flow logs can also be enabled to assist in troubleshooting the issue. With VPC flow logs enabled you can verify if traffic is reaching the EC2 instance and if there is any response traffic [5].
Additional: AWS provides detailed documentation on how to troubleshoot connectivity issues with EC2 instances, including step-by-step instructions for checking network configurations and resolving common issues [4].
References: [1] Security groups https://docs.aws.amazon.com/vpc/latest/userguide/vpc-security-groups.html
[2] Network access control list (NACL) https://docs.aws.amazon.com/vpc/latest/userguide/vpc-network-acls.html
[3] Internet Control Message Protocol (ICMP) https://aws.amazon.com/what-is/icmp/
[4] Instance connectivity issues https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/TroubleshootingInstancesConnecting.html
[5] Flow logs https://docs.aws.amazon.com/vpc/latest/userguide/flow-logs-cwl.html
[6] Internet gateway configurations (IGW) https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html
Relevant content
AWS OFFICIALUpdated 6 months ago
Can you provide the error you're receiving from SSH? It would be helpful if you ran your ssh command in verbose logging mode (e.g. ssh -vvv)