FTP protocol has two modes below.
1, the active mode: FTP server initiates a connection request to the client.
2. Passive mode: FTP server waits for a client initiates a connection request (the default operating mode of FTP).
Vsftpd service program
vsftpd as a more secure file transfer service that allows users to log in three authentication mode to an FTP server.
1, anonymous open mode (/ var / ftp): is one of the most insecure authentication mode, anyone can log on without a password verification directly to an FTP server.
2, the local user mode (local user's home directory): Linux system is through a local account password information for authentication mode, compared to anonymous open mode is more secure, and the configuration is also very simple. But if HK cracked account information, you can log in unimpeded FTP server, complete control over the entire server.
3, virtual user mode (mapping the user's home directory): This is the most secure of the three modes in an authentication mode, it needs to establish FTP service user database files separately, the virtual account information used for password verification, and the account information in the server system actually does not exist, only authenticate using the FTP service program.
NFS Network File System
. NFS (Network File System) service can file on a remote Linux system to mount shared resources directory on the local host, so that the local host (Linux clients) based on TCP / IP protocol, as it did read resources on the local host write a shared folder on a remote Linux system.
