Why does an Active FTP not work with network firewalls?

1.	Why does an Active FTP not work with network firewalls?
Answer» A firewall is established by typing a port number (or a range of port numbers) and an incoming or outgoing direction of traffic (active or passive FTP) into the rules. These two types of traffic require two different rules. A firewall must have two different rules for active FTP in order to allow these two kinds of traffic. The initiator in a push is external, whereas the initiator in a pull is internal. Active FTP is a unique application of ftp that requires different configurations.

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