Pascal Hambourg <pascal.mail@plouf.fr.eu.org> wrote:
Maxwillian Miorim a écrit :
> FTP traffic pass through ports 20 UDP and 21 TCP.
>
> First one "head" is established with an connection in UDP port 20,
> after this all traffic is exchanged through port 21 TCP.
Nonsense.
The FTP protocol uses only TCP, not use UDP. 21/TCP is the destination
port for the client -> server control connection. 20/TCP is the source
port in active mode for the server -> client data transfer connections.
20/TCP is not used in passive mode.
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I think Pascal is correct because He solved my problem. Before I did allow
tcp/udp 20 but still coudn't connect to ftp server. From what I know ftp use tcp. First ftp client is establishes a control connection between the client and server. Then a second connection is established to transfer data.