Java 7 prevents FTP transfers on Windows Vista and

问题:

Java 7 prevents FTP transfers on Windows Vista and 7.

In FTP, before a file is transferred a PORT or a PASV command must be sent. As soon as one of the commands is sent the Windows Firewall closes the socket that sent it. This only happens if the firewall is on and an exception for java.exe is absent. I suspect this problem is related to Java 7 using the new Vista IP stack.

Does anyone have any ideas how to fix or work around this problem? We're distributing a Java FTP library so we obviously can't add exceptions ourselves.

Exception:

java.net.SocketException: Permission denied: recv failed

JRE version info:

java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) 64-Bit Server VM (build 21.0-b17, mixed mode)

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FOLLOW-UP 1 (14 November 2011): Oracle has analysed the problem and have found that it seems to be a bug in Windows Firewall and/or the IPv6 stack. They managed to replicate the problem with a native C (i.e. non-Java) app, so this is strong evidence that the bug is not in Java. They have informed Microsoft, so the ball is in their court now. More details can be found at http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7077696

FOLLOW-UP 2 (27 July 2012): A (very helpful) contact at Oracle has told me that the issue has now been escalated at Microsoft. We're hoping to see some results soon.

FOLLOW-UP 3 (15 August 2012): Our contact at Oracle has told us that Microsoft has accepted the bug and is in the process of prioritizing it.

FOLLOW-UP 4 (21 September 2012): Microsoft has produced a patch that is currently being tested by Oracle. No word on a release date.

FOLLOW-UP 5 (11 October 2012): Success at last! Microsoft has publicly released a hotfix. They imply that the fix will be included in a general software update in the future:

"if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix."

回答1:

We tested the Windows hotfix http://support.microsoft.com/kb/2754804 and confirmed that it did resolve the problem.

回答2:

The problem is caused by the stateful FTP filter of the firewall. As a workaround you can disable it by executing netsh advfirewall set global StatefulFTP disable with administrator rights.

回答3:

I've submitted a bug report to Oracle, see bugs.sun.com/bugdatabase/view_bug.do?bug_id=7077696

They've marked the priority as low, which makes me think that they don't quite understand the magnitude of the problem, i.e. that FTP is broken on Java/Windows. I forgot to state that explicitly in the bug report. If anyone else feels like it should have a higher priority please add a comment to the Oracle bug report.

I just noticed that you can also 'vote' for the bug, so please give it a vote if you agree it's significant.

回答4:

Another workaround is to start the JVM with:

-Djava.net.preferIPv4Stack=true

回答5:

This problem can be demonstrated without JDK7, it's the firewall in Windows 7 blocking the ftp protocol when the application is using IPv6-mapped IPv4 addresses. See http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7077696 for more details and workarounds.

回答6:

Blogged about the issue here: http://podzemski.com/2011/09/12/java-7-prevents-ftp-transfers-on-windows-when-firewall-is-on/

Maybe it'll cause some additional awareness of the problem.

回答7:

Actually TFTP under JDK7 on windows 7 also have the same problem, the MS hotfix does resolve FTP issue, but still not works for TFTP. Seems Oracle should report the same problem to MS and get another hotfix to resolve TFTP issue as well.

回答8:

The same bug was reported here with a test case: Java 7 Socket Exception Bug forum. Its an issue with Java 7

回答9:

I had the same problem using IDE Eclipse Neon, JAVA 7 and Windows 7 Professional. Trying to upload a PDF file to an FTP server. I solved it by running the following command in CMD as administrator:

C: \ Users \ pc01> netsh advfirewall set global StatefulFTP disable