Hi All, Just wanted to update the findings on this issue. It was basically our firewall, and I suspect a good % of these "Control connection dead after successful file transfer" are caused by firewall timeouts.
Basically there is no traffic on the control connection while a huge file is being transferred and a firewall looking at the control connection as a plain tcp connection would come around and clear the connection (nat tables) assuming it to be idle. Finally when the file transfer is complete and the ftp client polls the control connection for "Transfer Complete", it times out with "Control connection appears dead" We fixed it by increasing our ftp service idle connection timeout on the firewall, not a robust solution, but works for relatively larger uploads. It still breaks for really large cases. This behavior is explained here: http://www.ncftp.com/ncftpd/doc/misc/ftp_and_firewalls.html: "Problems caused by the firewall prematurely timing out a valid FTP session" Thanks Sachin -----Original Message----- From: David Latorre [mailto:dvl...@gmail.com] Sent: Tuesday, December 13, 2011 12:04 AM To: ftpserver-users@mina.apache.org Subject: Re: FOUND THE REAL ISSUE - RE: Control connection closing on idle timeout even when data transfer is going on Hello Sachin, It seems this is a bug we should fix. Can you open a JIRA issue and provide a test case with it? 2011/12/10 Sachin Shetty <sshe...@egnyte.com> > I found the real issue here. I was misguided by Filezilla's dual connection > behavior where it always spawns a new connection for a data transfer and > leaved the original listing connection open. It's the listing connection > that times out, but the transfer connection is active and my assumption of > the root cause was wrong. > > > > My real problem is the issue reported in various other cases like: > > > http://mail-archives.apache.org/mod_mbox/mina-dev/201102.mbox/%3C987378340.1 > 0467.1297432017841.javamail.tom...@hel.zones.apache.org%3E > > > http://old.nabble.com/-jira--Created:-%28FTPSERVER-295%29-Connection-reset-b > y-peer,-help-td23269194.html > > > > I can reproduce this in filezilla, by setting a slow upload speed 1kbps, > causing the upload to go on for more than an hour. Filezilla transfers the > whole file and then fails with > > > > Error: Connection timed out > > Error: File transfer failed after transferring > 2,392,064 bytes in 2551 seconds > > > > > > FTP Logs: > > > > INFO 2011-12-10 15:48:54,134 pool-3-thread-54 D- U- S- > org.apache.ftpserver.command.impl.STOR - File uploaded > /Private/sshetty/9.doc > > INFO 2011-12-10 15:48:54,138 pool-3-thread-54 D- U- S- > org.apache.ftpserver.listener.nio.FtpLoggingFilter - SENT: 150 File status > okay; about to open data connection.^M > > > > INFO 2011-12-10 15:48:54,138 pool-3-thread-54 D- U- S- > org.apache.ftpserver.listener.nio.FtpLoggingFilter - SENT: 226 Transfer > complete.^M > > > > WARN 2011-12-10 15:48:54,138 pool-3-thread-54 D- U- S- > org.apache.ftpserver.listener.nio.FtpLoggingFilter - EXCEPTION : > > java.io.IOException: Connection reset by peer > > at sun.nio.ch.FileDispatcher.read0(Native Method) > > at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21) > > at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233) > > at sun.nio.ch.IOUtil.read(IOUtil.java:206) > > at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:236) > > at > > org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:214 > ) > > at > > org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:42) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPolling > IoProcessor.java:673) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPoll > ingIoProcessor.java:646) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPoll > ingIoProcessor.java:635) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractP > ollingIoProcessor.java:67) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(Abstra > ctPollingIoProcessor.java:1079) > > at > > org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java: > 64) > > at > > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.ja > va:886) > > at > > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:9 > 08) > > at java.lang.Thread.run(Thread.java:619) > > ERROR 2011-12-10 15:48:54,139 pool-3-thread-54 D- U- S- > org.apache.ftpserver.impl.DefaultFtpHandler - Exception caught, closing > session > > java.io.IOException: Connection reset by peer > > at sun.nio.ch.FileDispatcher.read0(Native Method) > > at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:21) > > at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:233) > > at sun.nio.ch.IOUtil.read(IOUtil.java:206) > > at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:236) > > at > > org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:214 > ) > > at > > org.apache.mina.transport.socket.nio.NioProcessor.read(NioProcessor.java:42) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.read(AbstractPolling > IoProcessor.java:673) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPoll > ingIoProcessor.java:646) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.process(AbstractPoll > ingIoProcessor.java:635) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor.access$400(AbstractP > ollingIoProcessor.java:67) > > at > > org.apache.mina.core.polling.AbstractPollingIoProcessor$Processor.run(Abstra > ctPollingIoProcessor.java:1079) > > at > > org.apache.mina.util.NamePreservingRunnable.run(NamePreservingRunnable.java: > 64) > > at > > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.ja > va:886) > > at > > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:9 > 08) > > at java.lang.Thread.run(Thread.java:619) > > INFO 2011-12-10 15:48:54,139 pool-3-thread-54 D- U- S- > org.apache.ftpserver.listener.nio.FtpLoggingFilter - CLOSED > > > > > > > > > > > > From: Sachin Shetty [mailto:sshe...@egnyte.com] > Sent: Monday, December 05, 2011 4:04 PM > To: 'Sachin Shetty'; 'ftpserver-users@mina.apache.org' > Subject: RE: Control connection closing on idle timeout even when data > transfer is going on > > > > anybody? > > > > this seems like a valid bug.. > > > > From: Sachin Shetty [mailto:sshe...@egnyte.com] > Sent: Sunday, December 04, 2011 1:56 PM > To: 'ftpserver-users@mina.apache.org' > Subject: Control connection closing on idle timeout even when data transfer > is going on > > > > We have configured our ftp servers to set idle timeout to 15 minutes. When > we are transferring huge files where it takes more than 15 minutes, the > control connection is closed by the server, while the data connection > continues as usual. > > > > I am not sure how the idle time out kicks in here, because even though > there > is no activity on the control connection, the data connection is active. > > > > Anybody faced same problem? > > > > Thanks > > Sachin > >
