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Gitblit server occasionally stops responding to SSH connections on port 29418

See original GitHub issue

Having upgraded to Gitblit 1.7.1 we are experiencing the following problem: Gitblit server occasionally stops responding to SSH connections on port 29418. This usually occurs once per day, once a couple of days.

In the server log one can find the following exception: 2016-01-13 13:18:56 [WARN ] Caught IOException while accepting incoming connection from /0:0:0:0:0:0:0:0:29418: The specified network name is no longer available.

java.io.IOException: The specified network name is no longer available.

at sun.nio.ch.Iocp.translateErrorToIOException(Iocp.java:309)
at sun.nio.ch.Iocp.access$700(Iocp.java:46)
at sun.nio.ch.Iocp$EventHandlerTask.run(Iocp.java:399)
at java.lang.Thread.run(Thread.java:745)

The last successful SSH session gets opened and closed just before this exception. No following SSH connections are possible any more. It seems as the socket accepting thread dies and the processing chain gets broken, preventing other following connection from processing.

Interestingly, other Gitblit services such as HTTPS, GIT, main page are operational.

The /0:0:0:0:0:0:0:0:29418 has suggested me that IPv6 might have been involved. I double checked the server set-up (Windows Server 2008 R2 (6.1)). The only existing Ethernet interface is bound to IPv4 only, no IPv6 is configured whatsoever.

I can bet the problem comes from way beneath Gitblit, and Gitblit is not to be blamed.

However I am considering some improvement in Gitblit alone, perhaps some exception handler, so that it is able to recover from such situation and be able to server following connections.

I would appreciate your comments and/or suggestions.

Dariusz