AWS EC2 SSH Login Troubleshooting: How to Resolve Connection Issues

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If you’re having trouble connecting to your AWS EC2 instance via SSH and getting a connection timed out message, don’t worry—there are several common issues to check that can help you find and fix the problem.

First, take a look at your network setup. Make sure your Virtual Private Cloud (VPC) has an Internet Gateway attached. This is essential for your instance to communicate with the internet. Next, verify that the route table for your subnet has a route pointing to the Internet Gateway; this usually means checking that there’s a route to 0.0.0.0/0 directed to the IGW. Also, confirm your instance is in a public subnet, which allows external access, and that it has a public IP address assigned.

Then, review your security settings. Double-check that your security group permits SSH traffic (port 22) from your IP address. Security groups are like virtual firewalls, so if your IP isn’t on the allowed list, you won’t connect. Additionally, review the network Access Control Lists (ACLs) for your subnet to ensure they permit inbound and outbound traffic on port 22. Remember, ACLs are stateless, so you need rules for both directions.

Next, check the status of your instance. Confirm it is running and has passed all system checks in the EC2 dashboard. You can also look at the system log for any errors during startup, which might hint at underlying issues.

If those settings look good, consider alternative ways to access your instance. If the Amazon Systems Manager (SSM) agent is installed on your machine, you can connect using Session Manager, bypassing SSH altogether. This method is especially helpful if your instance isn’t accessible through standard SSH.

When troubleshooting, try some quick steps. Use the public IP address directly instead of the DNS name, in case it’s a DNS resolution issue. Check if your operating system’s firewall might be blocking SSH connections. To dig deeper, enabling VPC Flow Logs on your network interface can help diagnose where traffic might be getting stuck. If nothing works, launching a new instance in a different subnet or region can help determine if the problem is specific to your current setup.

If you’ve gone through all these steps and still can’t connect, it might be worth creating a brand-new instance to see if the issue is related to the original configuration. Sometimes starting fresh can save time.

For more detailed guidance, you can check out resources like AWS documentation and troubleshooting guides for SSH connectivity issues. These sources provide additional tips and solutions to common problems.

Remember, troubleshooting can be a process of elimination; checking each of these areas systematically will increase your chances of successfully connecting to your AWS EC2 instance.