Linux——FTP file transfer service

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Table of contents

Foreword:

1. FTP file transfer service introduction

2. Build FTP file transfer service

1. Install vsftpd:

2. Edit the configuration file:

3. Restart the service:

4. Set FTP user:

5. Test:

3. Theoretical analysis - the main points of the article

4. Build FTP service based on virtual users

1. Create account data

2. Add virtual user support

3. Start the service and test

Foreword:

The Linux operating system provides a variety of FTP (File Transfer Protocol) file transfer services, including commonly used vsftpd and proftpd

1. FTP file transfer service introduction

FTP (File Transfer Protocol) is a common file transfer protocol used to transfer files between computers. The Linux operating system provides a variety of FTP file transfer services. Through these services, you can build an FTP server on the Linux system, so that other computers can access files through the FTP protocol.

Common Linux FTP services include vsftpd, proftpd, etc., among which vsftpd is one of the most commonly used FTP services. vsftpd is a very lightweight, fast, and secure FTP server originally designed for Red Hat, and now it has become the default FTP server for almost all Linux distributions.

2. Build FTP file transfer service

1. Install vsftpd:

sudo apt-get install vsftpd

2. Edit the configuration file:

sudo vim /etc/vsftpd.conf

3. Restart the service:

sudo service vsftpd restart

4. Set FTP user:

When adding an FTP user, be sure to add it to the appropriate user group

sudo adduser ftpuser
sudo usermod -aG ftp ftpuser

5. Test:

Use FTP software to connect to the FTP server for testing, enter the user name and password to access.

The above is the basic process of setting up the FTP file transfer service on the Linux system, and the specific operation can be adjusted according to the actual situation.

3. Theoretical analysis - the main points of the article

FTP connection method (type): ***
Control connection: TCP 21, used to send FTP command information
Data connection: TCP 20, for uploading and downloading data
FTP connection mode: ***
Active mode: the server actively initiates a connection to the client from port 20 (the server actively connects to the client)
Passive mode: the server passively waits for the client connection on a certain port within the specified range (the client actively connects to the server)
FTP transfer mode: ***
text mode, binary mode
Type of FTP user: ***
anonymous user, local user, virtual user
The main configuration file of Vsftpd:
/etc/vsftpd/vsftpd.conf
anonymous: anonymous
local: local
Daemon: daemon process; daemon

4. Build FTP service based on virtual users

1. Create account data

Create account database files for virtual FTP users
Create FTP root directory and system user for virtual user mapping
Create a PAM authentication file that supports virtual users

2. Add virtual user support

Add support configuration in vsftpd.conf file
Create separate configuration files for individual virtual users

3. Start the service and test

Reload vsftpd configuration
Use a virtual FTP account to access the test