0
A client can ask an FTP server to establish either a PASV (passive-default) or a PORT (active) connection for data transfer. Some servers are limited to only one type of connection. The difference between a passive and an active FTP connection lies in whether the client or server initiates the data connection. In passive mode, the client initiates the connection to the server (port 20-default(; in active mode, the server initiates the connection. Neither is inherently more secure than the other.
A Practical Guide to Fedora and Red Hat Enterprise Linux pg 644-Passive versus active connections
Wiki User
∙ 13y ago
Add your answer:
Earn +20 pts
Which two statements describe the FTP protocol?
The FTP client initiates the transfer of data when using a passive data connection. It requires two connections between client and server.
Why might you have problems connecting to an FTP server PORT mode?
Check the server has passive ftp enabled.
Which operating mode is generally necessary when running an FTP client behind a firewall?
PASV ("passive mode") is necessary when running a FTP client behind a firewall, as the default ("active mode") method will fail since the FTP server is unable to open a client to the client, usually because of NAT or firewall limitations.
Which network protocol uses port 21?
The network protocol that uses port 21 is FTP (File Transfer Protocol). FTP is commonly used for transferring files between a client and a server on a computer network. Port 21 is specifically designated for FTP control connections. When a user initiates an FTP connection, the client connects to the server's port 21 to establish communication for sending and receiving files. It is important to note that FTP operates in two modes: active mode and passive mode, each using different ports for data transfer.
How do you use a FTP client on a WiFi network?
There is no difference with FTP as a client on either a wired or wireless network; you use it the same way.
Explain the purpose of the file transfer protocol?
File Transfer Protocol (FTP) is used for transferring files between an FTP client and an FTP server.
What company offers the best free FTP client?
FTP clients are programs that enable large file transfers between servers and computers. Some good options for a free FTP client are Fire FTP, Cyberduck, and Core FTP LE.
What ports need to be open for the client to use the FTP client software?
FTP is a TCP based service exclusively. There is no UDP component to FTP. FTP is an unusual service in that it utilizes two ports, a 'data' port and a 'command' port (also known as the control port). Traditionally these are port 21 for the command port and port 20 for the data port. The confusion begins however, when we find that depending on the mode, the data port is not always on port 20. In active mode FTP the client connects from a random unprivileged port (N > 1023) to the FTP server's command port, port 21. Then, the client starts listening to port N+1 and sends the FTP command PORT N+1 to the FTP server. The server will then connect back to the client's specified data port from its local data port, which is port 20. From the server-side firewall's standpoint, to support active mode FTP the following communication channels need to be opened: * FTP server's port 21 from anywhere (Client initiates connection) * FTP server's port 21 to ports > 1023 (Server responds to client's control port) * FTP server's port 20 to ports > 1023 (Server initiates data connection to client's data port) * FTP server's port 20 from ports > 1023 (Client sends ACKs to server's data port) In order to resolve the issue of the server initiating the connection to the client a different method for FTP connections was developed. This was known as passive mode, or PASV, after the command used by the client to tell the server it is in passive mode. In passive mode FTP the client initiates both connections to the server, solving the problem of firewalls filtering the incoming data port connection to the client from the server. When opening an FTP connection, the client opens two random unprivileged ports locally (N > 1023 and N+1). The first port contacts the server on port 21, but instead of then issuing a PORT command and allowing the server to connect back to its data port, the client will issue the PASV command. The result of this is that the server then opens a random unprivileged port (P > 1023) and sends the PORT P command back to the client. The client then initiates the connection from port N+1 to port P on the server to transfer data. From the server-side firewall's standpoint, to support passive mode FTP the following communication channels need to be opened: * FTP server's port 21 from anywhere (Client initiates connection) * FTP server's port 21 to ports > 1023 (Server responds to client's control port) * FTP server's ports > 1023 from anywhere (Client initiates data connection to random port specified by server) * FTP server's ports > 1023 to remote ports > 1023 (Server sends ACKs (and data) to client's data port)
What is the similarities and differences between scp and ftp?
scp is secure copy ftp is file transfer protocol. FTP is a file transfer protocol as send the file inside the network
Fastest in between telnet ftp and tcp?
tcp
What is the difference between the put and the mput FTP subcommands?
The difference is that put transfers a single file, and mput can transfer multiple files- for instance, mput *20140506* would transfer all files with that date in the filename.
How do you write a short note on ftp?
FTP stands for file transfer protocol. FTP is used to transfer files between computers over the Internet. FTP servers can be setup to allow users to access the information anonymously or require registration for access.
