Fixed ssh_exchange_identification – connection closed by remote host

  • When using the SSH client to connect to a server, you might get an error message “SSH_exchange_identification: connection closed by remote host” This problem can have several causes, such as problems with the hosts. deny and hosts. allow configuration files.
  • Follow the steps outlined in this article to resolve the. problem to resolve.
  • The good news is that once the problem is resolved, you should no longer see this error.

 

Are you tired of encountering the frustrating “SSH Connection Closed by Remote Host” issue? We’ve got you covered! In this article, we will explore effective solutions to fix this problem once and for all. Say goodbye to interrupted SSH connections and hello to seamless remote access!

Check network connectivity: Ensure that both the client and the remote host have a stable network connection. A weak or intermittent connection can lead to the SSH connection being closed by the remote host.

Checking TCP wrapper files and adjusting connection limit

To fix the “SSH Connection Closed by Remote Host” issue, you may need to check and adjust the TCP wrapper files. These files control access to SSH connections and can limit the number of connections allowed.

First, locate the TCP wrapper configuration files. They are usually found in the /etc folder. Look for files named “hosts.allow” and “hosts.deny”.

Open the “hosts.allow” file using a text editor and add the following line to allow SSH connections:

sshd: ALL

Save the file and then open the “hosts.deny” file. Add the following line to deny all other SSH connections:

sshd: ALL

Save the file and restart the SSH service by running the command:

sudo systemctl restart ssh

This should fix the “SSH Connection Closed by Remote Host” issue by adjusting the connection limit in the TCP wrapper files. If the issue persists, consider checking other configuration files or seeking further assistance.

Removing remote host’s SSH public keys and trying to reconnect

To fix the “SSH Connection Closed by Remote Host” issue, you can try removing the remote host’s SSH public keys and then reconnecting. Here’s how:

1. Open your SSH client and locate the configuration file for the remote host. This file is usually located in the ~/.ssh/ directory.

2. Look for an entry in the configuration file that contains the identity file or public key for the remote host. Remove this entry.

3. Save the configuration file and exit your SSH client.

4. Now, try reconnecting to the remote host using the SSH client. You should no longer encounter the “Connection Closed by Remote Host” error.

This method helps resolve issues related to misconfigured public keys or conflicting entries in the configuration file. It’s a simple fix that can often solve the problem.

Remember to replace “remote host” with the actual hostname or IP address of the server you’re connecting to.

Fixing missing dependencies

Fixing SSH Connection Closed by Remote Host Issue

If you’re experiencing the “SSH Connection Closed by Remote Host” issue, it may be due to missing dependencies. Here are some steps to help you fix this problem:

1. Check your system for any missing dependencies that are required for SSH connections. Use the package manager on your system to install any necessary packages.

2. Ensure that your SSH client and server are both up to date with the latest updates and patches. Updating your system can often resolve compatibility issues and fix known bugs.

3. Verify that the SSH server is properly configured. Check the configuration file (typically located in /etc/ssh/sshd_config) for any incorrect settings or restrictions that may be causing the issue.

4. Make sure that your identity file (usually located in ~/.ssh/id_rsa or ~/.ssh/id_dsa) is correctly set up and matches the one specified in your SSH client configuration. Use the “ssh-keygen” command to generate a new identity file if needed.

5. If you’re connecting to a remote server, check if there are any server restrictions in place that could be causing the connection to close. Contact the server administrator for assistance with resolving these restrictions.

Checking for extra SSH sessions and server load

To check for extra SSH sessions and server load, follow these steps:

1. Open your SSH client and connect to the server.
2. Use the command “netstat -tnpa | grep ESTABLISHED” to check for active SSH sessions. This will display a list of established connections.
3. Look for any suspicious or unexpected connections. If you find any, consider terminating them using the “kill” command followed by the process ID (PID).
4. To check the server load, use the command “top“. This will display real-time information about CPU and memory usage, as well as running processes.
5. Pay attention to the CPU and memory usage percentages. If they are consistently high, it may indicate a server overload.
6. Consider optimizing your server configuration or adding additional resources to resolve the server load issue.

Remember to regularly monitor your SSH sessions and server load to ensure optimal performance and security.

Checking for corrupted fingerprint/keys

Checking for Corrupted Fingerprint/Keys:

If you are experiencing the “SSH Connection Closed by Remote Host” issue, it could be due to corrupted fingerprint/keys. To check for this, follow these steps:

1. Open a terminal or command prompt.

2. Enter the following command to access the SSH configuration file:
sudo nano /etc/ssh/sshd_config

3. Look for the line that starts with “HostKey“. This line contains the paths to the SSH keys used by the server. Make sure the paths are correct and the keys exist in those locations.

4. Next, check the permissions of the SSH key files. Use the command:
ls -l /path/to/ssh/keys
Ensure that the owner has read and write permissions, and that other users have read permissions.

5. If the keys or their permissions are incorrect, you can fix them by using the following commands:
sudo chmod 600 /path/to/ssh/keys
sudo chown username /path/to/ssh/keys

6. Save the changes to the SSH configuration file and exit.

7. Finally, restart the SSH service by running:
sudo service ssh restart

By checking and fixing any corrupted fingerprint/keys, you can resolve the “SSH Connection Closed by Remote Host” issue and regain access to your SSH server.

Identifying symptoms and solutions

  • Symptom: SSH connection closed by remote host error message
  • Solution 1: Check network connectivity and ensure the remote host is accessible
    Symptom: SSH connection closed by remote host error message
Solution 1: Check network connectivity and ensure the remote host is accessible
  • Solution 2: Verify SSH server configuration settings on the remote host
  • Solution 3: Confirm that the SSH service is running and properly configured on both the local and remote machines
  • Solution 4: Disable any firewalls or security software that may be blocking the SSH connection
  • Solution 5: Update or reinstall the SSH client software on the local machine
  • Solution 6: Restart the SSH service on both the local and remote machines
  • Solution 7: Check for any known issues or bugs related to the SSH client or server software versions
    Solution 6: Restart the SSH service on both the local and remote machines
Solution 7: Check for any known issues or bugs related to the SSH client or server software versions
  • Solution 8: Consult the SSH documentation or seek assistance from a technical support professional
  • Solution 9: Consider using an alternative SSH client or implementing a different remote access solution if the issue persists

Final words and about the author

Final Words:

In conclusion, resolving the “SSH Connection Closed by Remote Host” issue can be a challenging task. However, with the right knowledge and troubleshooting methods, it is possible to fix this problem and regain access to your server. By following the steps outlined in this article and considering the various factors that could be causing the issue, you can effectively troubleshoot and resolve the “SSH Connection Closed by Remote Host” error.

About the Author:

The author of this article is an experienced IT professional with a deep understanding of server-related issues and network troubleshooting. With a background in Windows 10 systems and server administration, the author has successfully resolved numerous cases of SSH connection issues. Their expertise in this area has been gained through years of hands-on experience, extensive research, and collaboration with peers. Their passion for problem-solving and helping others led to the creation of this article, which aims to provide practical solutions and guidance to those facing SSH connection closed issues.

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Mark Ginter is a tech blogger with a passion for all things gadgets and gizmos. A self-proclaimed "geek", Mark has been blogging about technology for over 15 years. His blog, techquack.com, covers a wide range of topics including new product releases, industry news, and tips and tricks for getting the most out of your devices. If you're looking for someone who can keep you up-to-date with all the latest tech news and developments, then be sure to follow him over at Microsoft.