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FTP PASV problem with Windows 7 firewall RRS feed

  • Question

  • Hello,

    we have implemented a simple FTP server for Windows CE. We experience strange problems if we try to use FTP passive mode from a client running under Windows 7 x64 while the firewall is enabled. It turned out that the response to the PASV command will be rejected from the firewall (even if we cannot find it in the log). More strange, it happens only if the address returned is not surrounded by parentheses:

    Request: PASV
    Response: 227 Entering Passive Mode 192,168,100,218,4,5

    will be rejected (The client engine sends a RST frame, the pending read on socket returns with error 10054 - Connection was forcibly closed).

    Request: PASV
    Response: 227 Entering Passive Mode (192,168,100,218,4,5)

    works fine. If the firewall is disabled both variants works well. We have checked the RFC related to FTP. The most relevant we found is the clarification in RFC 1123 which explicitely states that a client program MUST work without parentheses.

    Can you confirm or explain this behavior of the Windows 7 firewall (on XP we haven't seen anything like this).

    Thanks in advance
    Egmont Woitzel

    Monday, December 20, 2010 2:21 PM

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