Pure-ftp TLS: AUth Command Unsupported - Solution and Instructions

Pure-FTPd: AUth Command Unsupported - Solution Instructions

In this article, we will discuss the "AUth Command Unsupported" error in Pure-FTPd and provide step-by-step instructions to solve this issue. We will cover key concepts related to Pure-FTPd, TLS, and FTP clients. The article will be divided into several subtitles and paragraphs to ensure a clear and concise explanation of the topic.

Introduction

Pure-FTPd is a popular open-source FTP server that supports TLS encryption for secure file transfers. The "AUth Command Unsupported" error occurs when an FTP client attempts to use an unsupported authentication method. In this article, we will explain how to resolve this issue by creating a DH file, installing certificates, increasing the logging level, and configuring the FTP client.

Prerequisites

Before we begin, ensure that you have root access to your Pure-FTPd server and that you have installed Pure-FTPd and OpenSSL. Additionally, you should have an FTP client installed, such as FileZilla, to test the configuration.

Creating a DH File

The first step is to create a Diffie-Hellman (DH) file, which is used to generate a strong DH key for TLS encryption. To create a DH file, run the following command:

Installing Certificates

Next, we need to install the necessary certificates for TLS encryption. To generate a self-signed certificate, run the following command:

This command will generate a new RSA key and a self-signed certificate that is valid for 365 days. Make sure to replace the domain name and other information as necessary.

Increasing the Logging Level

To troubleshoot the "AUth Command Unsupported" error, we need to increase the logging level for Pure-FTPd. To do this, edit the /etc/pure-ftpd/pure-ftpd.conf file and add the following line:

This will increase the logging level to verbose mode, which will provide more detailed information about the FTP connections and authentication attempts.

Configuring the FTP Client

Finally, we need to configure the FTP client to use a supported authentication method. In FileZilla, this can be done by following these steps:

1. Open FileZilla and connect to the Pure-FTPd server.
2. Go to the "Edit" menu and select "Settings".
3. In the "Settings" window, go to "Connection > FTP".
4. Under "FTP", select "Require explicit FTP over TLS".
5. Under "Auth TLS", select "Ask for password" or "Use explicit FTP over TLS if available".
6. Click "OK" to save the changes.

This will configure FileZilla to use explicit FTP over TLS and to prompt for a password when connecting to the Pure-FTPd server.

Testing the Configuration

To test the configuration, connect to the Pure-FTPd server using FileZilla. If the configuration is correct, you should see a "TLS" message in the status bar, and the FTP connection should be established using TLS encryption.

• The "AUth Command Unsupported" error in Pure-FTPd occurs when an FTP client attempts to use an unsupported authentication method.
• To resolve this issue, create a DH file, install certificates, increase the logging level, and configure the FTP client to use a supported authentication method.
• In FileZilla, this can be done by selecting "Require explicit FTP over TLS" and "Auth TLS > Ask for password" or "Use explicit FTP over TLS if available" in the "Settings" window.

References

• Pure-FTPd documentation: https://www.pureftpd.org/project/pure-ftpd/doc/
• FileZilla documentation: https://wiki.filezilla-project.org/
• OpenSSL documentation: https://www.openssl.org/docs/