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How to Fix “Network Error: Software Caused Connection Abort” in Red Hat

Did you know that the “Network error: Software caused connection abort” message in Red Hat environments typically points to an unexpected closure of a network connection by the software, either on the client or server side?

This error is commonly encountered when using SSH clients like PuTTY or WinSCP to connect to a Red Hat Enterprise Linux system. It indicates that the underlying software has terminated the connection due to network issues, configuration problems, or resource limitations.

Understanding the Error

The error suggests that the connection was aborted, often by software on either the client or server. It may be related to network instability, misconfigurations, or insufficient system resources.

Here is the error syntax:

Network error: Software caused connection abort

The impacts of the error includes:

• Users are unable to establish or maintain a stable SSH connection.
• Automated scripts relying on SSH connections may fail, leading to potential disruptions in operations.
• Frequent disconnections cause decreased productivity and user dissatisfaction.

Common Causes and Fixes

1. Firewall Rules

Firewall settings may block or interrupt SSH traffic, causing the connection to drop.

Fix:

1. First, check current Firewall Rules:

   sudo firewall-cmd –list-all
2. Then, allow SSH Traffic. If SSH is not listed, add it using:

   sudo firewall-cmd --permanent –add-service=ssh
3. Next, reload firewall configuration:

   sudo firewall-cmd –reload
4. Then, confirm that SSH traffic is now allowed.

   sudo firewall-cmd –list-all

2. SSH Configuration

Incorrect settings in the SSH configuration file (`/etc/ssh/sshd_config`) may cause connection drops.

Fix:

1. First, open the SSH Configuration File:

   sudo nano /etc/ssh/sshd_config
2. Ensure the following lines are present and correctly set:

   ClientAliveInterval 60
ClientAliveCountMax 3


   Here, `ClientAliveInterval` defines how often the server sends a packet to keep the connection alive.

   Also, `ClientAliveCountMax` determines how many times to check before closing the connection.
3. Save changes and exit the editor (in Nano, press `CTRL + X`, then `Y`, then `Enter`).
4. Finally, restart SSH service:

   sudo systemctl restart sshd

3. Network Issues

Unstable network connections may cause SSH sessions to drop unexpectedly.

Fix:

1. Use `ping` to check connectivity.

   ping your_server_ip
2. Use Traceroute for detailed path analysis:

   traceroute your_server_ip

4. Resource Limitations

The server may be low on resources, such as CPU or memory, which can cause the connection to be terminated.

Fix:

1. Use `top` or `htop` to monitor resource usage.
2. Look for processes consuming excessive resources and terminate them if necessary.
3. If resource limitations are frequent, consider upgrading server hardware or optimizing our current setup.

5. Timeout Settings

Connection timeouts due to inactivity can cause disconnections.

Fix:

1. First, open PuTTY and go to Connection.
2. Then set “Seconds between keepalives” to a value (e.g., 60 seconds). This will send periodic keepalive signals to maintain the connection.
3. After adjusting the settings, return to the session screen and save the configuration.

6. Proxy Settings

Misconfigured proxy settings can cause SSH connections to fail.

1. For command-line clients, verify environment variables like `http_proxy` or `https_proxy`.
2. For GUI clients like PuTTY or WinSCP, check the proxy settings in their respective configuration panels.
3. Update or remove incorrect proxy settings as necessary.

7. Version Compatibility

Incompatibility between the SSH client and server versions can cause connection issues, especially if one is outdated.

Fix:

1. Check SSH Versions on Both Client and Server:
   • On the client side:

     ssh -V
   • On the server side (may require root access):

     sshd -V
2. Then, update SSH Software on the RHEL Server:

   sudo yum update openssh-server openssh-clients

Prevention Strategies

• Keep both client and server software updated to avoid compatibility issues and security vulnerabilities.
• Implement tools like Nagios or Prometheus to continuously monitor network performance, server health, and resource usage.
• Regularly backup configuration files (e.g., `/etc/ssh/sshd_config`) so that you can quickly restore settings in case of misconfigurations.
• Ensure that users are familiar with SSH best practices and troubleshooting techniques to minimize connection problems.

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Conclusion

The “Network error: Software caused connection abort” message can be frustrating, but it’s often caused by common issues such as firewall settings, SSH misconfigurations, or network instability. By following the troubleshooting steps outlined in this guide—adjusting firewall rules, optimizing SSH settings, monitoring resources, and keeping software updated—we can easily resolve this issue and maintain stable connections in Red Hat environments.

In brief, our Support Experts demonstrated how to fix RedHat Network Error Software Caused Connection Abort.