File Service & mdash; Vsftpd, service vsftpd

File Service-Vsftpd, service vsftpd

File Transfer Protocol (FTP ):

The file protocol that allows users to upload and download files on the Internet. The FTP service is a host that supports the FTP Transfer Protocol. To complete file transfer, the FTP server and the FTP client must work together.

Generally, you use the FTP client software to initiate a connection to the FTP server and send FTP commands. After receiving the USER command, the server returns the execution result to the client.

The FTP protocol occupies two ports:

Port 21: Command Control, used to receive FTP commands executed by the client

Port 20: data transmission for uploading and downloading file data

FTP data transmission type:

Active Mode: the FTP server initiates a connection request to the FTP client.

Passive Mode: the FTP server waits for connection requests from the FTP client.

Vsftpd: an FTP server program running on Unix-like operating systems.

Vsftpd program and configuration file:

 
Main Program/usr/sbin/vsftpd
 
User prohibited logon list/etc/vsftpd/ftpusers
 
/Etc/vsftpd/user_list
 
Main configuration file/etc/vsftpd. conf

Main configuration file of the Vsftpd program:

Cat/etc/vsftpd. conf

 
anonymous_enable=YES
local_enable=YES
write_enable=YES
local_umask=022
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
xferlog_std_format=YES
listen=YES
 
pam_service_name=vsftpd
userlist_enable=YES
tcp_wrappers=YES

Vsftpd configuration file parameters:

 
 
 
Listen = [YES | NO]
Whether to listen to the service independently.
Listen_address = IP Address
Set the IP address to listen.
Listen_port = 21
Set the listening port of the FTP service.
Download_enable = [YES | NO]
Whether to allow file download.
Userlist_enable = [YES | NO]
Userlist_deny = [YES | NO]
Whether to enable "forbidden login username list ".
Max_clients = 0
Maximum number of client connections. 0 is unlimited.
Max_per_ip = 0
The maximum number of connections from the same IP address. The value 0 is not limited.
Anonymous_enable = [YES | NO]
Whether anonymous user access is allowed.
Anon_upload_enable = [YES | NO]
Whether Anonymous Users are allowed to upload files.
Anon_umask = 022
Umask value of the File Uploaded by an anonymous user.
Anon_root =/var/ftp
The FTP root directory of anonymous users.
Anon_mkdir_write_enable = [YES | NO]
Whether Anonymous Users are allowed to create directories.
Anon_other_write_enable = [YES | NO]
Whether to enable other write permissions for anonymous users.
Anon_max_rate = 0
The maximum transmission rate (in bytes) of anonymous users. 0 is unlimited.
Local_enable = [YES | NO]
Whether to allow local users to log on to FTP.
Local_umask = 022
Umask value of the File Uploaded by the local user.
Local_root =/var/ftp
The FTP root directory of the local user.
Chroot_local_user = [YES | NO]
Whether to block user permissions in the FTP directory is more secure.
Local_max_rate = 0
The maximum transmission rate (in bytes) of local users. 0 is unlimited.

Vsftpd verification method:

Vsftpd provides an optional authentication method for ftp services: Anonymous Access, local users, and virtual users.

 
Anonymous Access: Anyone can log on to the FTP server without a verification password.
 
Local User: Use the user and password information on the FTP server.
 
Virtual User: create an independent FTP account.

Anonymous access is generally used to store public data. Local Users and virtual users must provide accounts and passwords to log on to the FTP service. Virtual users are the safest.