A. Check that installed vsftpd
vsftpd -v
II. Installation vsftpd
apt-get install vsftpd
III. Check that good vsftpd installed
vsftpd -v
Four first check iptables settings:
#iptables -nL
Protective wall method: https://i.cnblogs.com/EditPosts.aspx?opt=1
V. view the port situation
iptables -nL
VI. Set up an FTP service
Load ip_conntrack_ftp, complete structures
#modprobe ip_conntrack_ftp
NOTE: In the INPUT iptables "1 ACCEPT all - 0.0.0.0/0 0.0.0.0/0 state RELATED, ESTABLISHED" may be achieved pasv ftp connections
Quote:
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FTP protocol has two modes: PORT mode and PASV mode, Chinese meant to active and passive.
Port Mode: FTP Server: TCP 21 is <------ Client: Dynamic FTP Server: TCP 20 is ------> Client: Dynamic
Pasv mode: ftp server: tcp 21 <---- client: dynamic ftp server: tcp dynamic <---- client: dynamic
Connection process PORT (active) mode are: FTP client to the server port (default 21) transmits a connection request, the server accepts the connection, establishing a link command. When you need to transfer data, the client tells the server on the command link with the PORT command: "I opened the XXXX port, you connect me to come." Thus XXXX server port 20 from the port sends a connection request to the client to establish a data link to transmit data.
Connection process the PASV (passive) mode are: FTP client to the server port (default 21) transmits a connection request, the server accepts the connection, establishing a link command. When you need to transfer data, the server on the command link tells the client to use PASV command: "I opened the XXXX port, you connect me to come." Thus the client request sent to the port connection XXXX server, establishing a data link to transmit data.