What is Active FTP vs Passive FTP (A Definitive Explanation)

1. What is the difference between Active FTP and passive FTP?
2. What is passive FTP?
3. How do I know if my FTP is active or passive?
4. Should I use passive FTP mode?
5. Why is passive FTP preferred?
6. How do I change from passive to active FTP?
7. How does FTP passive mode work?
8. What is Passive FTP port range?
9. How do I allow passive FTP through firewall?
10. How do modern firewalls and routers deal with active FTP connections?
11. Why does active FTP not work with network firewalls?
12. What is the command to check passive mode is active or not?

What is the difference between Active FTP and passive FTP?

In an active mode connection, when the client makes the initial connection and sends PORT, the server initiates the second connection back. In a passive connection, the client connects and sends the PASV command, which functions as a request for a port number to connect to.

What is passive FTP?

Passive FTP is an FTP mode that can be requested by a client to alleviate the issues caused by client-side firewalls. Both the server and the client must support passive FTP for this process to work. When passive FTP is used, the client will initiate the connection to the server.

How do I know if my FTP is active or passive?

From ftp client, to check if remote ftp server support passive mode, after login, type quote PASV . The ftp command quote send all arguments following it to remote server. Remote server will process them as command/request if applicable. PASV is a request for server to use passive mode.

Should I use passive FTP mode?

In passive mode FTP, the FTP client initiates both connections to the server. ... This method of FTP is insecure, as a random unprivileged port is opened on the Server. This is a potential security issue and it isn't advisable to use the Passive mode of FTP.

Why is passive FTP preferred?

Using the passive mode is preferable because most of the complex configuration is done only once on the server side, by experienced administrator, rather than individually on a client side, by (possibly) inexperienced users. Use Passive mode session settings to toggle between the active and the passive mode.

How do I change from passive to active FTP?

Once you have logged into the site with FTP, type passive and then do your transfer. Just run passive within the client. Passive mode changes the method used for connecting to the FTP, as active mode often encounters issues with more restrictive firewall rules.

How does FTP passive mode work?

Passive mode FTP

In passive mode, the client still initiates a command channel connection to the server. However, instead of sending the PORT command, it sends the PASV command, which is basically a request for a server port to connect to for data transmission.

What is Passive FTP port range?

Most clients select passive mode transfers for FTPS by default. To avoid extreme ranges - for example, "allow TCP from all to ports 1024-65535" - specific ranges of inbound passive ports can be configured on both your FTP server and your firewall.

How do I allow passive FTP through firewall?

Double-click the passive FTP server.
...
Option B: Allow the Intrusion Prevention rule

1. From the DSM, click Policies > Policies.
2. Click the policy to be applied on the FTP server, and then click Details.
3. In the new window, click Firewall > Assign/Unassign…
4. Assign the following rule to the policy: FTP server (Default Rule)

How do modern firewalls and routers deal with active FTP connections?

The firewall will intercept the information in the PASV command and allow outbound access to the high-number port on the FTP server from the FTP client until the communication is complete. This prevents the need to open outbound access to all high-number ports for PASV-mode FTP clients.

Why does active FTP not work with network firewalls?

Typically firewalls don't allow any incoming connections at all, which frequently blocks active FTP from functioning. ... The reason is that the firewall is blocking the return connection from the server to the client (from port 20 on the server to a high port on the client).

What is the command to check passive mode is active or not?

1 Answer. Passive mode is enabled by issuing the PASV command to the server. If it responds with an error code (should be 500 Unknown command ) upon issuing that command, then you know that it is not supported. If it responds with a 227 Entering Passive Mode , then you know that passive is supported.