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https://issues.apache.org/jira/browse/SSHD-781?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16223312#comment-16223312
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Goldstein Lyor commented on SSHD-781:
-------------------------------------
I am not sure I understand exactly what you are trying to accomplish and why
this heartbeat issue with the _wantReply=true_ is so crucial so I don't feel I
can give you an exact answer. A few remarks though:
{quote}
the sshServer will reponse a SSH_MSG_REQUEST_FAILURE, What's the influence？
{quote}
Even if there is no (visible) influence it is bad practice to send requests
that you know cause failures - even if these failures do not (seem to) cause
any (visible) effect.
{quote}
I'm more concerned about client connection status changes in time when Client
and server network unreachable
{quote}
If you want to know what the client's status is - I repeat my suggestion to
register a _SessionListener_ and thus be informed of any change in your session
- including read timeout.
Finally, the mechanism that was inspired from your comments is described on
SSHD-782 - i.e., usage of periodic server-side {{SSH_MSG_IGNORE}} messages to
avoid having the client time out on read. If you decide to go down this path,
please feel free to post a pull-request with your suggestion, and if it passes
review we will be happy to incorporate it into the code (with credit tou you...)
> The heartbeat task of client not support keepalive function well
> ----------------------------------------------------------------
>
> Key: SSHD-781
> URL: https://issues.apache.org/jira/browse/SSHD-781
> Project: MINA SSHD
> Issue Type: Question
> Affects Versions: 1.4.0, 1.6.0
> Environment: Any environment
> Reporter: MayDay
> Assignee: Guillaume Nodet
> Labels: test
> Fix For: 1.7.0
>
>
>
> The heartbeat request of sshClient is a SSH_MSG_GLOBAL_REQUEST, but
> the default buffer of heartbeat set false (see
> [ClientConnectService#sendHeartbeat|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/client/session/ClientConnectionService.java])
> {code:java}
> buf.putBoolean(false);
> {code}
> The sshServer reponse the heartbeat by the
> [KeepAliveHandler|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/server/global/KeepAliveHandler.java],
> then [AbstractConnectionService
> #sendGlobalResponse|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractConnectionService.java].
> {code:java}
> boolean wantReply = buffer.getBoolean();
> {code}
> but if the buffer of heartbeat set false, then the sendGlobalResponse
> will not reponse sshClient {color:#205081}because of the wantReply is
> false{color} .(see [AbstractConnectionService
> #globalRequest|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/common/session/helpers/AbstractConnectionService.java])
> {code:java}
> if (RequestHandler.Result.Replied.equals(result) || (!wantReply)) {
> return new AbstractIoWriteFuture(req, null) {
> {
> setValue(Boolean.TRUE);
> }
> };
> }
> {code}
> 1 、Is it a Bug(set the heartbeat buffer false default)? how the sshClient
> know the server is available when the server don't response.
> I have test it whth create a client with params (
> HEARTBEAT_INTERAL = 60
> IDLE_TIMEOUT = 300
> NIO_READ_TIMEOUT = 315)and a server, and the client will close seesion after
> the NIO_READ_TIMEOUT.
> 2、If the client reach the NIO_READ_TIMEOUT, then thows a
> {color:#8eb021}InterruptedByTimeoutException{color},and close the session.But
> the task of heratbeat not stoped, it will continue to run even though it will
> not send packet.See the
> [ClientConnectionService
> #startHeartBeat|https://github.com/apache/mina-sshd/blob/693fa5d90f54676de6655954046a8a4f5d09728a/sshd-core/src/main/java/org/apache/sshd/client/session/ClientConnectionService.java]
> {code:java}
> service.scheduleAtFixedRate(this::sendHeartBeat, interval, interval,
> TimeUnit.MILLISECONDS);
> {code}
> if the sshClient reopen a new session and close it many times,the number of
> invalid scheduling heartbeat task will become very large, it's not
> equitable.
>
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