diff --git a/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala
index a79095daa3..8292b861e7 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala
@@ -98,9 +98,7 @@ class TcpSpec extends StreamSpec("""
         .toMat(Sink.ignore)(Keep.left)
         .run()
 
-      whenReady(future.failed) { ex ⇒
-        ex.getMessage should ===("Connection failed.")
-      }
+      future.failed.futureValue shouldBe a[StreamTcpException]
     }
 
     "work when client closes write, then remote closes write" in assertAllStagesStopped {
@@ -456,6 +454,19 @@ class TcpSpec extends StreamSpec("""
       }
     }
 
+    "provide full exceptions when connection attempt fails because name cannot be resolved" in {
+      val unknownHostName = "abcdefghijklmnopkuh"
+
+      val test =
+        Source.maybe
+          .viaMat(Tcp().outgoingConnection(unknownHostName, 12345))(Keep.right)
+          .to(Sink.ignore)
+          .run()
+          .failed
+          .futureValue
+
+      test.getCause shouldBe a[UnknownHostException]
+    }
   }
 
   "TCP listen stream" must {
diff --git a/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala b/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala
index a746337f06..b921f276cd 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/io/TcpStages.scala
@@ -235,8 +235,8 @@ private[stream] object ConnectionSourceStage {
       val sender = evt._1
       val msg = evt._2
       msg match {
-        case Terminated(_)          ⇒ failStage(new StreamTcpException("The IO manager actor (TCP) has terminated. Stopping now."))
-        case f @ CommandFailed(cmd) ⇒ failStage(new StreamTcpException(s"Tcp command [$cmd] failed${f.causedByString}"))
+        case Terminated(_)          ⇒ fail(new StreamTcpException("The IO manager actor (TCP) has terminated. Stopping now."))
+        case f @ CommandFailed(cmd) ⇒ fail(new StreamTcpException(s"Tcp command [$cmd] failed${f.causedByString}").initCause(f.cause.orNull))
         case c: Connected ⇒
           role.asInstanceOf[Outbound].localAddressPromise.success(c.localAddress)
           connection = sender
@@ -275,10 +275,10 @@ private[stream] object ConnectionSourceStage {
           if (!isClosed(bytesIn) && !hasBeenPulled(bytesIn))
             pull(bytesIn)
 
-        case Terminated(_)          ⇒ failStage(new StreamTcpException("The connection actor has terminated. Stopping now."))
-        case f @ CommandFailed(cmd) ⇒ failStage(new StreamTcpException(s"Tcp command [$cmd] failed${f.causedByString}"))
-        case ErrorClosed(cause)     ⇒ failStage(new StreamTcpException(s"The connection closed with error: $cause"))
-        case Aborted                ⇒ failStage(new StreamTcpException("The connection has been aborted"))
+        case Terminated(_)          ⇒ fail(new StreamTcpException("The connection actor has terminated. Stopping now."))
+        case f @ CommandFailed(cmd) ⇒ fail(new StreamTcpException(s"Tcp command [$cmd] failed${f.causedByString}").initCause(f.cause.orNull))
+        case ErrorClosed(cause)     ⇒ fail(new StreamTcpException(s"The connection closed with error: $cause"))
+        case Aborted                ⇒ fail(new StreamTcpException("The connection has been aborted"))
         case Closed                 ⇒ completeStage()
         case ConfirmedClosed        ⇒ completeStage()
         case PeerClosed             ⇒ complete(bytesOut)
@@ -346,16 +346,25 @@ private[stream] object ConnectionSourceStage {
             else interpreter.log.debug(msg + "\n{}", remoteAddress, ex, ex.getStackTrace.mkString("\n"))
           }
           connection ! Abort
-        } else failStage(ex)
+        } else fail(ex)
       }
     })
 
-    override def postStop(): Unit = role match {
-      case Outbound(_, _, localAddressPromise, _, _) ⇒
-        // Fail if has not been completed with an address earlier
-        localAddressPromise.tryFailure(new StreamTcpException("Connection failed."))
-      case _ ⇒ // do nothing...
+    /** Fail stage and report to localAddressPromise if still possible */
+    private def fail(ex: Throwable): Unit = {
+      reportExceptionToPromise(ex)
+      failStage(ex)
     }
+    private def reportExceptionToPromise(ex: Throwable): Unit =
+      role match {
+        case Outbound(_, _, localAddressPromise, _, _) ⇒
+          // Fail if has not been completed with an address earlier
+          localAddressPromise.tryFailure(ex)
+        case _ ⇒ // do nothing...
+      }
+
+    override def postStop(): Unit = reportExceptionToPromise(new StreamTcpException("Connection failed."))
+
     writeBuffer = ByteString.empty
   }
 }