'Server 2019 Windows Firewall Blocking FTP Traffic With Port 21 and 20 Allowed

Hey i have a C# written software that try to download files via FTP. On my local machine it works fine. But on the server its blocked by the firewall. With firewall of it works. I allready added port 20 and port 21 to the rules. The Software works with passive mode.

Connection the the FTP works and it read the files and directorys. But by trying to download a file it get timeout.

Any Idea?

c++sharpftpfirewallwindows-serverwindows-firewall


Solution 1:[1]

On my azure FTP server, I had to open ports 7000-7014 to allow the data stream for file transfer.

Here is a good article on what's going on. https://www.techrepublic.com/article/how-ftp-port-requests-challenge-firewall-security/

Essentially, you can connect on 20,21 but the actual file transfer happens on some higher port number that the server will tell the client to connect on.

Sources

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Source: Stack Overflow

Solution Source
Solution 1 TechneWare

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