Paramiko.ssh_exception.sshexception server not found in known_hosts

Greetings Dev! Have you been experiencing the error message paramiko.ssh_exception.sshexception server not found in known_hosts? This can be a frustrating problem, but fear not! In this article, we will dive into the causes and solutions for this issue, as well as provide some helpful tips and FAQs to help you troubleshoot effectively.

What is Paramiko?

Before we dive into the specific issue of paramiko.ssh_exception.sshexception server not found in known_hosts, let’s first define what Paramiko is. Paramiko is a Python implementation of the SSH protocol, which is used to securely connect to remote servers and execute commands. It is a valuable tool for developers and system administrators who need to manage multiple servers, as it allows for easy automation and scripting of tasks.

How does Paramiko work?

Paramiko functions through two key components: the client and the server. The client is the computer or device that initiates the connection, while the server is the computer or device that accepts the connection. The client uses the Paramiko library to establish a secure SSH connection with the server, and can then execute commands or transfer files over this connection.

When a client connects to a server for the first time, the server’s public key is stored in the client’s known_hosts file. This file contains a list of trusted servers that the client has connected to in the past, and is used to verify the identity of servers during subsequent connections. If a server’s key is not present in the known_hosts file, or if the key has changed since the last connection, Paramiko will throw the error paramiko.ssh_exception.sshexception server not found in known_hosts.

Causes of paramiko.ssh_exception.sshexception server not found in known_hosts

There are several potential causes for the error message paramiko.ssh_exception.sshexception server not found in known_hosts. These include:

1. Missing or incorrect server key

If the server’s public key is missing or incorrect in the client’s known_hosts file, Paramiko will not be able to verify the server’s identity and will throw the error message. This can occur if the server is new and has not yet been added to the known_hosts file, or if the server’s key has changed since the last connection.

2. DNS resolution issues

The error message can also occur if there are DNS resolution issues preventing the client from connecting to the specified server. This can be due to a variety of reasons, such as incorrect DNS settings or a temporary server outage.

3. Firewall or security restrictions

In some cases, the error message can be caused by firewall or security restrictions that prevent the client from connecting to the server. This can occur if the server is located behind a firewall that blocks incoming SSH connections, or if the client is using incorrect authentication credentials.

Solutions for paramiko.ssh_exception.sshexception server not found in known_hosts

Now that we have explored some of the potential causes for the error message paramiko.ssh_exception.sshexception server not found in known_hosts, let’s discuss some solutions to this problem.

1. Add the server’s key to the known_hosts file

If the error message is caused by a missing or incorrect server key in the client’s known_hosts file, the solution is to add the correct key to the file. This can be done manually by copying and pasting the server’s public key into the known_hosts file, or automatically by connecting to the server and accepting the key when prompted.

2. Check DNS resolution and network connectivity

If the error message is caused by DNS resolution issues, the solution is to check the client’s DNS settings and network connectivity. This can be done by pinging the server’s IP address or hostname, and verifying that the client can establish a connection to the server using other tools such as Telnet.

3. Verify firewall and security settings

If the error message is caused by firewall or security restrictions, the solution is to verify that the client is using the correct authentication credentials and that the server is not located behind a firewall that blocks SSH connections. It may be necessary to consult with system administrators or IT professionals to resolve these issues.

Frequently Asked Questions

Conclusion

Paramiko.ssh_exception.sshexception server not found in known_hosts can be a frustrating issue for those using Paramiko, but it is not insurmountable. By understanding the potential causes and solutions for this error message, developers and system administrators can effectively troubleshoot and resolve this issue. Remember to always verify authentication credentials, check DNS resolution and connectivity, and add servers to the known_hosts file as needed.