FTP (File Transfer Protocol)

FTP is well known when it comes to transferring files between the client and the server over a network. There are two types of voice namely: Active and Passive.

What is Active FTP?

Consider that Active FTP is a mode of FTP, where the client initiates a connection on port and waits for the server to establish connection with it. In this mode of working the client opens the command channel and the server opens the data channel. To some extent, this may lead to arising of security challenges because the client has to open ports for incoming connections.

Advantages of Active FTP

• Simpler Server Configuration: Since the server is the one to open the data connection, it minimizes the server's complexity.
• Efficient for Trusted Networks: It is effective especially most of the time when the client and the server are in the same trusted network.

Disadvantages of Active FTP

• Firewall Issues: Well, most firewalls limit incoming connections and that further makes Active FTP a tricky proposition.
• Not Ideal for Client Security: Affects client's accessibility by making them open up ports meaning that unknown parties can have easy access to the network.

What is Passive FTP?

The common mode implemented is the passive FTP since the client opens both the command and data connections, which make it more appropriate when working with firewalls or NATs. The server informs the client on the port to establish for the data channel.

Advantages of Passive FTP

• Firewall-Friendly: Good, in conjunction with firewalls and NAT since all connections in the client-server model are made by the client.
• Enhanced Security: It also minimizes the risks of security since the client's default incoming connections are minimized and controlled.

Disadvantages of Passive FTP

• Server Configuration Complexity: It requires the server to handle several ports as well as connection, which serves a higher level of difficult.
• Potential for Higher Resource Usage: When it comes to the server-side configuration, there is more complex setting, it means that more resources are being used.

Differences between Active and Passive FTP

Active FTP	Passive FTP
Client establishes the command channel and the server establishes the data channel.	Both the command channel and the data channel are established by the client.
Active FTP provides security to the FTP server.	Passive FTP does not provide security to the FTP server.
Active FTP may cause problems because of firewalls.	Passive FTP does not have connection issues from firewalls.
Active mode is not used as a default mode of a browser.	Passive mode is used as a default mode of a browser.
FTP client acknowledges on data channel.	FTP server acknowledges on data channel.
Client sends random port number to the server.	Client sends PASV command to the server.
In Active FTP, the data connection is made and the file transfers are then done through  client and server ports.	In passive FTP, the client still have to initiates the command channel (control connection) to the server.

Conclusion

Active and Passive FTP are two protocols that need to be distinguished if a person wants to create a safe and fast connection for files exchange. Nevertheless there are disadvantages and clinging to Active FTP may be easier for a server side but it results in the number of security threats for a client side. While Passive FTP is less efficient than Active FTP but is safe for clients and require more configurations from the firewall but causes trouble in the server. In general, the use of Active or Passive FTP will depend with the user needs and the networks architecture at hand.