Build an FTP server in Linux

Source: Linux Community luzhi1024

Build an FTP server in Linux.

FTP works by starting two channels:
Control channel, data channel
In the FTP protocol, the control connection is initiated by the client, and there are two modes of data connection: Port mode (active mode) and PASV (passive mode)
Port mode:
When the client needs to receive data, the ftp_client (random port greater than 1024)-port command->ftp_server (21) sends the port command, which contains the port that the client uses to receive data (a random port greater than 1024). When data is transferred, Ftp_server will establish a new connection to transmit data through its own TCP 20 port and the ports contained in port.

PASV mode:
When transmitting data, the FTP_CLIENT--PASV command-->ftp_server (21) sends the PASV command, Ftp_server automatically opens a random port between 1024--5000 and notifies FTP_ The client transmits the data on this port, and then the clients make a request connection to the specified port and establish a data link to transmit it.
Install FTP
#rpm-qa vsftpd See if you have installed

#yum install-y vsftpd

#rpm-QL vsftpd
/etc/logrotate.d/vsftpd. Log files for vsftpd
/ETC/PAM.D/VSFTPD Pam Certification File
/ETC/RC.D/INIT.D/VSFTPD Startup scripts
directory where the/etc/vsftpd vsftpd configuration file is stored
/etc/vsftpd/ftpusers prohibit the use of VSFTPD user list files
/etc/vsftpd/user_list prohibit or allow the use of VSFTPD user list files
/ETC/VSFTPD/VSFTPD.CONF Master configuration file
/etc/vsftpd/vsftpd_conf_migrate.sh Some variables and settings for VSFTPD operations
/USR/SBIN/VSFTPD VSFTPD's main program
Some other explanatory documents and manuals file slightly!
/var/ftp Anonymous User home directory
/var/ftp/pub download directory for anonymous users

#service vsftpd Start
#chkconfig--level vsftpd
#chkconfig--level 2345 vsftpd on

2 Login name for anonymous User: FTP (anonymous) password empty, login directory is/var/ftp
When logged in with an anonymous user, the default is only download permissions, no upload, create and delete permissions:

#vim/etc/vsftpd/vsftpd.conf
Anon_upload_enable=yes Upload
Anon_mkdir_write_enable=yes Create
Anon_other_write_enable=yes Delete
#service vsftpd Restart

Anonymous users should be prevented from logging in for security purposes:
123456 #vim/etc/vsftpd/vsftpd.conf
Anonymous_enable=no
#anon_upload_enable =yes Upload
#anon_mkdir_write_enable =yes Create
#anon_other_write_enable =yes Delete
#service vsftpd Restart

3 Create a login directly to the system user to log in to ftp:
#useradd-S/sbin/nologin viong
#passwd Viong

User has upload create download switch directory
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4 Strengthening VSFTP security settings:
Restrict system users from locking home directories:
#vim/etc/vsftpd/vsftpd.conf
Chroot_list_enable=yes
Chroot_list_file=/etc/vsftpd/chroot_list limit more users of the system, the need to restrict users to join the/etc/vsftpd/chroot_list can
#touch/etc/vsftpd/chroot_list
#cut-D:-F 1/etc/passwd >>/etc/vsftpd/chroot_list add Local users to Chroot_list

Restrict critical system users from logging on to ftp:
#cat/etc/vsftpd/ftpusers Some of the more important users in the system have been added by default
#echo "Viong" >>/etc/vsftpd/ftpusers at this time Viong cannot log on to FTP

Use FTP user policy to allow system users to log on to ftp:
/etc/vsftpd/user_list only users in this file can log in to the system:
#vim/etc/vsftpd/vsftpd.conf
#在userlist_enable =yes Add the following
Userlist_deny=no
Userlist_file=/etc/vsftpd/user_list

Set logon FTP Destination IP address: set with Iptables

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Build VSFTPD to support SSL encrypted transmission:
#openssl req-x509-nodes-days 365-newkey Rsa:1024-keyout/etc/vsftpd/vsftpd.pem-out/etc/vsftpd/vsftpd.pem Generate certificate
#vim/etc/vsftpd/vsftpd.conf
Ssl_enable=yes
Allow_anon_ssl=no
Force_local_data_ssl=yes
Force_local_logins_ssl=yes
Ssl_tlsv1=yes
Ssl_sslv2=yes
Ssl_sslv3=yes
Rsa_cert_file=/etc/vsftpd/vsftpd.pem

Here are some definitions of SSL parameters to modify according to your needs:

Ssl_enable=yes/no//Whether SSL is enabled, default is no
Allow_anon_ssl=yes/no//Whether to allow anonymous users to use SSL, default to No
Rsa_cert_file=/path/to/file the location of the//RSA certificate
Dsa_cert_file=/path/to/file the location of the//DSA certificate
Force_local_logins_ssl=yes/no//Non-anonymous user is encrypted when logged on, default is yes
Force_local_data_ssl=yes/no//Non-anonymous user is encrypted when transferring data, default is Yes
force_anon_logins_ssl=yes/no//Anonymous user is encrypted when logged on, default is no
force_anon_data_ssl=yes/no//Anonymous user is encrypted when data transfer, default is no
Ssl_sslv2=yes/no//Whether to activate SSLV2 encryption, default No
Ssl_sslv3=yes/no//Whether to activate SSLv3 encryption, default No
Ssl_tlsv1=yes/no//Whether to activate TLS v1 encryption, default Yes
Ssl_ciphers= encryption method//default is Des-cbc3-sha

#service vsftpd Restart

Connect with Flashftp:
Connection type: FTP uses public SSL (verify SSL)
Address: 192.168.137.130:21
Login type: Normal
Users: Viong
Password: 123

FTP virtual user see: Http://www.linuxidc.com/Linux/2015-06/118443.htm

Four high-level configurations for VSFTPD server: http://www.linuxidc.com/Linux/2013-09/90565.htm

VSFTPD Configuration Tutorial: http://www.linuxidc.com/Linux/2013-09/90562.htm

CentOS 7 Installation Configuration FTP server http://www.linuxidc.com/Linux/2014-11/109233.htm

Ubuntu Utility Simple FTP Erection http://www.linuxidc.com/Linux/2012-02/55346.htm

Set up an FTP server and Apache server on Ubuntu http://www.linuxidc.com/Linux/2011-04/35295.htm

Ubuntu 13.04 Installation lamp\vsftpd\webmin\phpmyadmin services and Settings http://www.linuxidc.com/Linux/2013-06/86250.htm

A simple case of anonymous uploading of SELinux and VSFTPD under the RHEL6 platform http://www.linuxidc.com/Linux/2013-04/82300.htm

Linux system VSFTPD Source Installation http://www.linuxidc.com/Linux/2013-03/81475.htm

OpenSUSE 13.2/13.1 Under Install configure FTP server VSFTPD http://www.linuxidc.com/Linux/2014-12/110070.htm

This article permanently updates the link address : http://www.linuxidc.com/Linux/2015-06/118442.htm

Build an FTP server in Linux