Kibana - socket hang up error

[stackoverflower]

I am running Kibana behind IIS reverse proxy server and getting following error

*Courier Fetch Error: unhandled courier request error: socket hang up
I am on Version: 4.2.2, Build: 9177. *
I get this error only when I use proxy server which I need to restrict access to Kibana. I am not sure what is causing this or how to fix it.

Error: unhandled courier request error: socket hang up
at handleError (http://kibana-server/bundles/kibana.bundle.js:70047:23)
at DocRequest.AbstractReqProvider.AbstractReq.handleFailure (http://kibana-server/bundles/kibana.bundle.js:69967:15)
at http://kibana-server/bundles/kibana.bundle.js:69861:18
at Array.forEach (native)
at http://kibana-server/bundles/kibana.bundle.js:69859:19
at wrappedErrback (http://kibana-server/bundles/commons.bundle.js:39286:79)
at http://kibana-server/bundles/commons.bundle.js:39419:77
at Scope.$eval (http://kibana-server/bundles/commons.bundle.js:40406:29)
at Scope.$digest (http://kibana-server/bundles/commons.bundle.js:40218:32)
at Scope.$apply (http://kibana-server/bundles/commons.bundle.js:40510:25)

Originally discussed as part of Issue#3110 but posting it as a new issue since that one is marked as closed.

[rashidkpc]

Does this happen without the proxy in place? From the sound of your ticket it sounds like it doesn't, which would point to the proxy itself being the issue. Possibly a timeout configuration issue? Please join us at http://discuss.elastic.co for support

[LeeDr]

I'm adding some notes to this closed issue based on Kibana 4.6.4 testing just for informational purposes.

Short summary is that these appear to be harmless errors. I haven't seen any UI issues with this in the browser and everything in Kibana seems to work fine when this type of log error occurs. I didn't see anybody else report any UI problems related to these log errors either.

If I have Elasticsearch 2.4.4 with license and shield plugins
and Kibana 4.6.4 with shield plugin.

The Kibana Shield plugin requires SSL configuration, but I'm using some test cert which was not created for this machine or issued by a trusted authority. That could be the cause of these errors. I could generate certs that are better, but not completely trusted so I'm not going to spend too much time on that.

If I start Kibana and open a new incognito Chrome browser window (I'm on Windows) and go to https://localhost:5601 I see it says Not Secure by the URL because of my cert. But no errors in Kibana console output.

If I open a new IE 11 private window and go to https://localhost:5601 Kibana immediately logs;

 log   [18:51:30.985] [error][client][connection] Error: socket hang up
   at TLSSocket.<anonymous> (_tls_wrap.js:822:25)
   at emitOne (events.js:101:20)
   at TLSSocket.emit (events.js:188:7)
   at Socket._handle.close (net.js:498:12)
   at Socket.g (events.js:291:16)
   at emitOne (events.js:101:20)
   at Socket.emit (events.js:188:7)
   at TCP._handle.close [as _onclose] (net.js:498:12)
 log   [18:51:30.996] [error][client][connection] Error: socket hang up
   at TLSSocket.<anonymous> (_tls_wrap.js:822:25)
   at emitOne (events.js:101:20)
   at TLSSocket.emit (events.js:188:7)
   at Socket._handle.close (net.js:498:12)
   at Socket.g (events.js:291:16)
   at emitOne (events.js:101:20)
   at Socket.emit (events.js:188:7)
   at TCP._handle.close [as _onclose] (net.js:498:12)

When I click Continue to this website (not recommended). in IE 11 I get 2 more errors in the log.
But I can log in to Kibana and there's no sign of a problem.

Microsoft Edge browser causes the same errors in the Kibana log as IE 11.

When I try Firefox I get a different error in the log (but again, everything works fine in the browser);

 log   [18:53:39.178] [error][client][connection] Error: 0:error:14094418:SSL routines:ssl3_read_bytes:tlsv1 alert unknown ca:openssl\ssl\s3_pkt.c:1487:SSL alert number 48

   at Error (native)

[rashmivkulkarni]

@LeeDr : should we re-open this ?am not sure if this will be fixed for 4.6.4 though ? thoughts ?

[LeeDr]

I'm assuming these errors in the log are caused by are invalid certs because Firefox, IE, and Edge all cause them in my scenario and they all also fail to load Kibana until you negotiate the insecure certificate acceptance.
And Chrome loads Kibana immediately and doesn't cause the errors in the log.

If had had completely valid certs from a trusted authority for the host Kibana was running on and we still saw the errors, then I think we should do something about it. Even if that's just to suppress the error from being logged.