2、FTP：使用20/21端口。主要是用来传输文件，比如建站常常用来上传主页或者下载文件进行修改，FTP是一个8位的客户端-服务器协议，能操作任何类型的文件而不需要进一步处理，就像MIME或Unicode一样。但是，FTP有着极高的延时，这意味着，从开始请求到第一次接收需求数据之间的时间，会非常长。3、SMTP：使...
FTP has been officially assigned ports 20 and 21. If specifically using an “active” connection setting, this means that while a client computer makes the connection request and sends the commands first on port 21, known as the “control port,” a connection to the server on port 20, the...
As an application layer protocol, FTP is used for file transfer between remote server and local client. FTP uses TCP ports 20 and 21 for data transfer and control command transfer respectively. Basic FTP operations are described in RFC 959. FTP-based file transmission is performed in the follow...
FTP is an unusual service in that it utilizes two ports, a 'Data' port and a 'CMD' (command) port. Traditionally these are port 21 for the command port and port 20 for the data port. FTP can be used in two modes, active and passive. Depending on the mode, the data port is not...
632 - Confidentiality and integrity protected reply. 633 - Confidentiality protected reply. Common FTP status codes and their causes 150 - FTP uses two ports: 21 for sending commands, and 20 for sending data. A status code of 150 indicates that the server is about to open a new connection ...
Standard FTP ports can be ports 20 and 21 since FTP was officially assigned both. Port 21 is referred to as a controlled port, while port 20 is the data port. Port 21 builds a connection with the server, as port 21 automatically opens to transfer the file data. The algorithm applies to...
As an application layer protocol, FTP is used for file transfer between remote server and local client. FTP uses TCP ports 20 and 21 for data transfer and control command transfer respectively. Basic FTP operations are described in RFC 959. FTP-based file transmission is performed in the follow...
The one exception to this is if you host multiple servers on the same IP but using different ports, however this requires that the connecting client uses a non-standard port and therefore is probably not a good solution for mass hosting. Is there anything in the pipeline to fix this? There...
For Active connections open ports 20 and 21 For Passive connections open ports 21 and 1024+ (and higher) Also, turn off command filtering on the firewall. If you still cannot get a successful connection, check all devices that are between the client and server to ensure that the proper por...
The File Transfer Protocol (FTP) is an application layer protocol. FTP is an unusual service in that it utilizes two ports, a 'Data' port and a 'CMD' (command) port. Traditionally these are port 21 for the command port and port 20 for the data port. FTP can be used in two modes,...