Install and build FTP server under Linux system

FTP is the file Transfer Protocol protocol, which is a protocol designed to transfer files. Simply put, a server that supports the FTP protocol is an FTP server.

FTP supports two modes: PORT (Active), PASV (passive).

Port mode: First the FTP client and the server TCP 21 port to establish a connection, and then send the port command on this channel, the command contains the client with a port connection, the server receives the command will use the data port (20) to connect the client that port.

PASV mode: When an FTP connection is turned on, the client randomly opens two non-privileged ports A and B, where a port establishes a connection to the server's TCP 21 port, and the client sends the PASV command to the server on the command channel, and the server receives a random open non-privileged port p. The port command is then sent to the client, and the client receives a P port that is connected to the server using B port to transmit the data.

Install FTP

#rpm-qa vsftpd See if you have installed

Installing vsftpd-y #yum Install

#service vsftpd start Start service

#ftp 192.168.254.5 (IP address) login

Response code

1XX: Information

2XX: Success Class Code

3xx: Prompt to further manipulate class code

4XX: Client Error

5XX: Service-side error

How to sign In

Configuration file/etc/vsftpd/vsftpd.conf

Anonymous user settings:

Anonymous_enable=yes whether anonymous users are enabled

Anon_upload_enable=yes Upload

Anon_mkdir_write_enable=yes Creating a Directory

Anon_other_write_enable=yes Delete

Restrict system users from locking home directories:

Chroot_list_enable=yes Limit All

Chroot_list_enable=yes part of the limit

Chroot_list_file=/etc/vsftpd/chroot_list will need to restrict users from writing to this file

System users in the/etc/vsftpd/ftpusers file will be blocked from logging in

Number of connections limit:

max_clients=# FTP Server maximum number of access clients

max_per_ip=# maximum number of connections per IP

Transfer Rate Limit:

anno_max_rate=# Maximum transfer rate for anonymous users

Anonymous users:

User name: FTP; password is empty; login directory:/var/ftp.

System users:

User name: local user; password: user password; login directory: User home directory.

Pam_service_name=vsftpd

Virtual Login

Create a custom name file under/etc/vsftpd/, odd-numbered user names, even-numbered behavior passwords; All virtual user directories are a system home directory.

1. Create User Password text

Vim/etc/vsftpd/vftpuser

User1

Redhat1

User2

Redhat2

2. Generate the Virtual user authentication db file

Db_load-t-T Hash-f/etc/vsftpd/vftpuser/etcvsftpd/vftpuser.db

3. Edit the Pam file

Method One, vi/etc/pam.d/vsftpd content all commented out, add the following two sentences

Auth Required/lib (/security/pam_userdb.so) db=/etc/vsftpd/vftpuser

Account Required/lib (/security/pam_userdb.so db=/etc/vsftpd/vftpuser)

Method Two, create a new file under/etc/pam.d/Vsftpdauth, write the above two sentences, and then edit the configuration file vsftpd.conf.

Pam_service_name=vsftpdauth change to the file name you created

4, create a system user, all virtual users are mapped to this system user

useradd-d/home/vftp-s/sbin/nologin Virtual user name is virtual

chmod 700/home/vftp Set permissions

5, enable the virtual user in the configuration file, add the following parameters:

Guest_enable=yes

Guest_username=virtual

Restarting the FTP service

Install and build FTP server under Linux system