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https://issues.apache.org/jira/browse/SSHD-901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16778422#comment-16778422
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Goldstein Lyor commented on SSHD-901:
-------------------------------------

{quote}
I'm not proposing that the server sends a keep alive global request, I'm simply 
proposing that it responds to one initiated by the client. But yes I am using 
the Mina SSHD server too.
{quote}
This only re-enforces what I said - if the server on the other side is not MINA 
SSHD, this mechanism might fail

{quote}
I just looked into the OpenSSH client and it sends its [email protected] 
request with want reply true.1

Do you think adding a configuration property for the keep alive that specifies 
how long to wait for a reply is an option? If the property is set to greater to 
zero we set "want reply" true and wait for that period of time for a response 
via AbstractSession.request().
{quote}
Acceptable, but in order to avoid backward compatibility issues the default 
will be zero - i.e., no reply expected. This means that users will have to 
*activate* this option *explicitly* while taking full responsibility for any 
incompatible behavior.

{quote}
I'm not proposing that the server sends a keep alive global request, I'm simply 
proposing that it responds to one initiated by the client
{quote}
We can do that, but how would we recognized the global request ? In your test 
code you are using {{CloudConnectClient.KEEP_ALIVE}} whose value I don't see. 
Please note that the SSHD client sends a global request configured via 
{{"heartbeat-request"}} property whose default value is 
{{"[email protected]"}}, In order for the server to correctly answer it 
it must know about it - something which will be left to the user. I.e., the it 
is the *user;s* responsibility to configure *both* client and server (as you 
have done in your sample code).

> InterruptedByTimeoutException occurring in client despite keepalive global 
> request being sent
> ---------------------------------------------------------------------------------------------
>
>                 Key: SSHD-901
>                 URL: https://issues.apache.org/jira/browse/SSHD-901
>             Project: MINA SSHD
>          Issue Type: Bug
>    Affects Versions: 2.2.0
>         Environment: Windows 10
>            Reporter: Jared Wiltshire
>            Priority: Major
>
> This may be related to SSHD-891 but I couldn't follow that issue exactly.
> I was noticed that after exactly 10 minutes and 15 minutes a 
> java.nio.channels.InterruptedByTimeoutException exception was being thrown by 
> the client. After a little digging I discovered that this is the default 
> value for NIO2_READ_TIMEOUT. This is the stack trace -
> {code:java}
> ERROR 2019-02-25T17:25:16,879 
> (com.infiniteautomation.mango.cloudConnect.client.CloudConnectClient$ClientSessionListener.sessionException:83)
>  - Session exception, session 
> ClientSessionImpl[mango@localhost/127.0.0.1:9005] 
> java.nio.channels.InterruptedByTimeoutException: null
>       at 
> sun.nio.ch.WindowsAsynchronousSocketChannelImpl$ReadTask.timeout(WindowsAsynchronousSocketChannelImpl.java:614)
>  ~[?:1.8.0_144]
>       at 
> sun.nio.ch.WindowsAsynchronousSocketChannelImpl$2.run(WindowsAsynchronousSocketChannelImpl.java:649)
>  ~[?:1.8.0_144]
>       at 
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) 
> ~[?:1.8.0_144]
>       at java.util.concurrent.FutureTask.run(FutureTask.java:266) 
> ~[?:1.8.0_144]
>       at 
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
>  ~[?:1.8.0_144]
>       at 
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
>  ~[?:1.8.0_144]
>       at 
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
>  ~[?:1.8.0_144]
>       at 
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
>  ~[?:1.8.0_144]
>       at java.lang.Thread.run(Thread.java:748) [?:1.8.0_144]
> {code}
> Now I have the heat beat interval (ClientFactoryManager.HEARTBEAT_INTERVAL) 
> property set to less than 10 minutes and I verified that the global request 
> is indeed being sent and received by the server.
> However I think that the issue is that the global request is sent with 
> wantReply set to false. So the server does not reply with anything and the 
> client does not read any data from the socket and hence times out.
> Does it not make sense for the server to reply? I believe this is a self 
> defined global request (not in the SSH RFC) so we should be able change its 
> behavior.



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