Knowledge Base

Introduction

Pure-FTPd is a secure, fast, and easily configurable FTP server commonly used on Linux and Unix-like systems. However, you may sometimes encounter an "Active: failed (Result: timeout)" error after installation or update. This error indicates that the Pure-FTPd service could not be started and timed out. This guide will help you understand the causes of this problem and apply step-by-step solutions. Correct FTP server installation, configuration, and security settings are critical to preventing such errors.

1. Causes of Error and Basic Checks

1.1. Network Connection Problems

One of the most common causes is problems with the server's network connection. Check if the server has internet access. DNS resolution issues can also cause this error.

• Solution: Test the internet connection with the ping google.com command. If you cannot ping, check your network settings. Make sure the correct DNS servers are defined in the /etc/resolv.conf file.

1.2. Firewall Settings

The firewall may be blocking FTP traffic. Make sure that the ports used by Pure-FTPd (usually 21 and a dynamic port range for passive mode) are open in the firewall.

• Solution: Check the settings of iptables, firewalld, or other firewall software you are using. For example, if you are using firewalld, you can allow FTP service to pass through with the following commands:

sudo firewall-cmd --permanent --add-service=ftp
sudo firewall-cmd --reload

1.3. Incorrect Configuration File

The pure-ftpd.conf file may be configured incorrectly. Incorrect parameters in this file can prevent the service from starting.

• Solution: Carefully examine the /etc/pure-ftpd/pure-ftpd.conf file. Check for incorrect or missing lines. In particular, make sure that parameters such as PassivePortRange and ForcePassiveIP are set correctly.

1.4. Port Conflict

Port 21 may be used by another service. In this case, Pure-FTPd cannot be started.

• Solution: Check which service is using port 21 with the netstat -tulnp | grep :21 command. If another service is using it, stop that service or run Pure-FTPd on a different port.

1.5. Insufficient System Resources

The server may have insufficient system resources such as memory or processor. In this case, the Pure-FTPd service may time out.

• Solution: Monitor system resource usage with the top or htop commands. If resources are overloaded, stop unnecessary services or provide more resources to the server.

1.6. Disk Space Issues

Running out of disk space can prevent Pure-FTPd from writing log files or creating temporary files. This can prevent the service from starting.

• Solution: Check disk space with the df -h command. If the disk is full, delete unnecessary files or expand the disk space.

2. Systemd Related Issues

2.1. Service File Accuracy

The systemd configuration file (pure-ftpd.service) for the Pure-FTPd service may be incorrect.

• Solution: Check the /lib/systemd/system/pure-ftpd.service or /etc/systemd/system/pure-ftpd.service file. Make sure parameters such as ExecStart, User, and Group are set correctly.

2.2. Reloading Systemd Daemon

The systemd daemon may need to be reloaded after configuration changes.

• Solution: Reload the systemd daemon and restart the Pure-FTPd service using the following commands:

sudo systemctl daemon-reload
sudo systemctl restart pure-ftpd

2.3. Checking Service Status

Checking the status of the service can help determine the source of the problem.

• Solution: Check the status of the service with the sudo systemctl status pure-ftpd command. Examine the error messages and look for clues for a solution.

3. Reviewing and Correcting the Configuration File

3.1. Basic Configuration Parameters

Make sure the following parameters are set correctly in the pure-ftpd.conf file:

• Listen: The IP address and port the FTP server will listen on.
• PassivePortRange: The port range to be used for passive mode.
• ForcePassiveIP: The IP address to be used in passive mode.
• PureDB: The path to the user database.
• AnonymousOnly: Whether only anonymous access is allowed.
• NoAnonymous: Whether anonymous access is blocked.

3.2. Sample Configuration File

Below is an example of a basic pure-ftpd.conf file:

Listen                      192.168.1.10:21
PassivePortRange            30000 30100
ForcePassiveIP              192.168.1.10
PureDB                      /etc/pure-ftpd/pureftpd.pdb
AnonymousOnly               no
NoAnonymous                 no
MaxClientsNumber            50
MaxClientsPerIP             5

3.3. Testing the Configuration File

After making changes to the configuration file, it is important to test the file.

• Solution: Test the configuration file with the pure-ftpd -t command. Examine the error messages and make corrections.

4. User Accounts and Permissions

4.1. Checking the User Database

Pure-FTPd stores user accounts in a database. Make sure that this database is created correctly and that users have the correct permissions.

• Solution: Display the user's information with the pure-pw show command. If necessary, add, edit, or delete users with the pure-pw useradd, pure-pw usermod, pure-pw userdel commands.
• Important: After making changes to the database, recreate the database with the pure-pw mkdb command.

4.2. Checking File Permissions

Make sure that the files and directories that users are trying to access have the correct permissions.

• Solution: Check the permissions of files and directories with the ls -l command. If necessary, change the permissions and ownership with the chmod and chown commands.

5. Passive Mode Issues and Solutions

5.1. Correctly Setting the Passive Port Range

Make sure that the port range used for passive mode is open in the firewall and set correctly in the configuration file.

• Solution: Set the PassivePortRange parameter correctly in the pure-ftpd.conf file. Usually, a range such as 30000-30100 or 49152-65534 is used. Don't forget to open this range in the firewall.

5.2. Specifying the External IP Address

Specify the server's external IP address with the ForcePassiveIP parameter. This is especially important for servers behind NAT.

• Solution: Set the ForcePassiveIP parameter with the server's external IP address. If the server has a dynamic IP address, you can use a DNS service to associate it with a domain name.

5.3. NAT and Forwarding Settings

If the server is behind a NAT, make the necessary port forwardings in the router to forward FTP traffic to the server.

• Solution: In your router's settings, forward port 21 and the passive port range to the server's local IP address.

6. Examining Log Files

6.1. Location of Log Files

Pure-FTPd log files are usually located in the /var/log/syslog or /var/log/pure-ftpd/ directory.

6.2. Examining Log Files

By examining log files, you can determine the cause of errors. For example, failed login attempts, file permission issues, or network connection problems can be seen in the log files.

• Solution: Monitor log files in real-time with the tail -f /var/log/syslog or tail -f /var/log/pure-ftpd/pureftpd.log commands. Examine error messages and look for clues for a solution.

7. Real-Life Examples and Case Studies

7.1. Case Study 1: Firewall Issue

A user was getting a "Timeout" error after installing Pure-FTPd. Upon examining the log files, they found that the connections were being blocked by the firewall. The problem was resolved after allowing the FTP service through the firewall.

7.2. Case Study 2: Passive Mode Configuration

Another user was trying to run Pure-FTPd on a server behind NAT. They were experiencing connection problems because they had not configured passive mode correctly. The problem was resolved after correctly setting the ForcePassiveIP parameter and performing the necessary port forwarding on the router.

8. Visual Explanations (Textual Descriptions)

8.1. FTP Connection Diagram

An FTP connection takes place between the client and the server over two channels: the control channel (port 21) and the data channel (dynamic port range in passive mode). The control channel is used to send commands and receive responses, while the data channel is used for file transfer.

8.2. Firewall Diagram

The firewall controls incoming and outgoing traffic, preventing unauthorized access. For FTP traffic to pass smoothly, port 21 and the port range used for passive mode must be open in the firewall.

9. Frequently Asked Questions

• 9.1. How do I restart Pure-FTPd?
• You can restart Pure-FTPd with the command sudo systemctl restart pure-ftpd.
• 9.2. How do I configure passive mode?
• You can configure passive mode by setting the PassivePortRange and ForcePassiveIP parameters in the /etc/pure-ftpd/pure-ftpd.conf file.
• 9.3. How do I add a user?
• You can add a user with the command pure-pw useradd -u -d . Then, don't forget to recreate the database with the pure-pw mkdb command.
• 9.4. Why am I getting a "Timeout" error?
• The "Timeout" error can be caused by various reasons such as network connection problems, firewall settings, incorrect configuration file, port conflict, or insufficient system resources. You can identify and resolve the source of the problem by following the steps in this guide.
• 9.5. Which ports do I need to open?
• You need to open port 21 for FTP and the port range you configured for passive mode (e.g., 30000-30100) in the firewall.

10. Conclusion and Summary

The Pure-FTPd "Timeout" error is a complex problem that can be caused by various reasons. In this guide, we have addressed the possible causes of this problem and step-by-step solutions in detail. Checking network connection problems, adjusting firewall settings, examining the configuration file, checking user accounts and permissions, correctly configuring passive mode, and examining log files are the basic steps you need to take to solve the problem. I hope this guide helps you resolve the Pure-FTPd "Timeout" error and run a secure, fast, and reliable FTP server.

Important Notes:

• Before making any changes, back up the configuration files.
• When running commands, make sure you have the correct user rights (you usually need to use sudo).
• If the problem persists, refer to the Pure-FTPd documentation and forums.

Additional Information and Resources

• Pure-FTPd Official Website
• Arch Linux Wiki: Pure-FTPd
• Ubuntu Community Help Wiki: Pure-FTPd

Tables

Table 1: Pure-FTPd Configuration Parameters Comparison

Table 2: Pure-FTPd Error Codes and Meanings