diff --git a/client/daemon/peer/peertask_conductor.go b/client/daemon/peer/peertask_conductor.go
index 6c5311e0d..955bcbdfe 100644
--- a/client/daemon/peer/peertask_conductor.go
+++ b/client/daemon/peer/peertask_conductor.go
@@ -1164,6 +1164,8 @@ func (pt *peerTaskConductor) ReportPieceResult(request *DownloadPieceRequest, re
 		code = base.Code_ClientConnectionError
 	} else if isPieceNotFound(err) {
 		code = base.Code_ClientPieceNotFound
+	} else if isBackSourceError(err) {
+		code = base.Code_ClientBackSourceError
 	}
 	pt.reportFailResult(request, result, code)
 }
diff --git a/client/daemon/peer/piece_downloader.go b/client/daemon/peer/piece_downloader.go
index c7c07b0c2..a6baa84db 100644
--- a/client/daemon/peer/piece_downloader.go
+++ b/client/daemon/peer/piece_downloader.go
@@ -70,6 +70,10 @@ type pieceDownloadError struct {
 	err             error
 }
 
+type backSourceError struct {
+	err error
+}
+
 func isConnectionError(err error) bool {
 	if e, ok := err.(*pieceDownloadError); ok {
 		return e.connectionError
@@ -84,6 +88,13 @@ func isPieceNotFound(err error) bool {
 	return false
 }
 
+func isBackSourceError(err error) bool {
+	if _, ok := err.(*backSourceError); ok {
+		return true
+	}
+	return false
+}
+
 func (e *pieceDownloadError) Error() string {
 	if e.connectionError {
 		return fmt.Sprintf("connect with %s with error: %s", e.target, e.err)
@@ -91,6 +102,10 @@ func (e *pieceDownloadError) Error() string {
 	return fmt.Sprintf("download %s with error status: %s", e.target, e.status)
 }
 
+func (e *backSourceError) Error() string {
+	return e.err.Error()
+}
+
 var _ PieceDownloader = (*pieceDownloader)(nil)
 
 var defaultTransport http.RoundTripper = &http.Transport{
diff --git a/client/daemon/peer/piece_manager.go b/client/daemon/peer/piece_manager.go
index 60876fa1e..29e553aee 100644
--- a/client/daemon/peer/piece_manager.go
+++ b/client/daemon/peer/piece_manager.go
@@ -23,6 +23,7 @@ import (
 	"math"
 	"net"
 	"net/http"
+	"net/url"
 	"time"
 
 	"golang.org/x/time/rate"
@@ -333,13 +334,13 @@ func (pm *pieceManager) downloadKnownLengthSource(ctx context.Context, pt Task,
 		}
 		if err != nil {
 			log.Errorf("download piece %d error: %s", pieceNum, err)
-			pt.ReportPieceResult(request, result, err)
+			pt.ReportPieceResult(request, result, detectBackSourceError(err))
 			return err
 		}
 
 		if result.Size != int64(size) {
 			log.Errorf("download piece %d size not match, desired: %d, actual: %d", pieceNum, size, result.Size)
-			pt.ReportPieceResult(request, result, err)
+			pt.ReportPieceResult(request, result, detectBackSourceError(err))
 			return storage.ErrShortRead
 		}
 
@@ -356,7 +357,7 @@ func (pm *pieceManager) downloadKnownLengthSource(ctx context.Context, pt Task,
 				})
 			if err != nil {
 				log.Errorf("update task failed %s", err)
-				pt.ReportPieceResult(request, result, err)
+				pt.ReportPieceResult(request, result, detectBackSourceError(err))
 				return err
 			}
 		}
@@ -401,7 +402,7 @@ func (pm *pieceManager) downloadUnknownLengthSource(ctx context.Context, pt Task
 			},
 		}
 		if err != nil {
-			pt.ReportPieceResult(request, result, err)
+			pt.ReportPieceResult(request, result, detectBackSourceError(err))
 			log.Errorf("download piece %d error: %s", pieceNum, err)
 			return err
 		}
@@ -412,7 +413,7 @@ func (pm *pieceManager) downloadUnknownLengthSource(ctx context.Context, pt Task
 		} else if result.Size > int64(size) {
 			err = fmt.Errorf("piece %d size %d should not great than %d", pieceNum, result.Size, size)
 			log.Errorf(err.Error())
-			pt.ReportPieceResult(request, result, err)
+			pt.ReportPieceResult(request, result, detectBackSourceError(err))
 			return err
 		}
 
@@ -430,7 +431,7 @@ func (pm *pieceManager) downloadUnknownLengthSource(ctx context.Context, pt Task
 			})
 		if err != nil {
 			log.Errorf("update task failed %s", err)
-			pt.ReportPieceResult(request, result, err)
+			pt.ReportPieceResult(request, result, detectBackSourceError(err))
 			return err
 		}
 		// content length is aligning at piece size
@@ -446,3 +447,11 @@ func (pm *pieceManager) downloadUnknownLengthSource(ctx context.Context, pt Task
 	log.Infof("download from source ok")
 	return nil
 }
+
+func detectBackSourceError(err error) error {
+	// TODO ensure all source plugin use *url.Error for back source
+	if e, ok := err.(*url.Error); ok {
+		return &backSourceError{err: e}
+	}
+	return err
+}
diff --git a/client/daemon/peer/piece_manager_test.go b/client/daemon/peer/piece_manager_test.go
index 0d292251a..391136ae6 100644
--- a/client/daemon/peer/piece_manager_test.go
+++ b/client/daemon/peer/piece_manager_test.go
@@ -234,3 +234,59 @@ func TestPieceManager_DownloadSource(t *testing.T) {
 		})
 	}
 }
+
+func TestDetectBackSourceError(t *testing.T) {
+	assert := testifyassert.New(t)
+	testCases := []struct {
+		name              string
+		genError          func() error
+		detectError       bool
+		isBackSourceError bool
+	}{
+		{
+			name: "is back source error - connect error",
+			genError: func() error {
+				_, err := http.Get("http://127.0.0.1:12345")
+				return err
+			},
+			detectError:       true,
+			isBackSourceError: true,
+		},
+		{
+			name: "is back source error - timeout",
+			genError: func() error {
+				client := http.Client{
+					Timeout: 10 * time.Millisecond,
+				}
+				request, _ := http.NewRequest(http.MethodGet, "http://127.0.0.2:12345", nil)
+				_, err := client.Do(request)
+				return err
+			},
+			detectError:       true,
+			isBackSourceError: true,
+		},
+		{
+			name: "not back source error",
+			genError: func() error {
+				return fmt.Errorf("test")
+			},
+			detectError:       true,
+			isBackSourceError: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			err := tc.genError()
+
+			err = detectBackSourceError(err)
+			if tc.detectError {
+				assert.NotNil(err)
+			} else {
+				assert.Nil(err)
+			}
+
+			assert.Equal(tc.isBackSourceError, isBackSourceError(err))
+		})
+	}
+}
diff --git a/pkg/rpc/base/base.pb.go b/pkg/rpc/base/base.pb.go
index a55ea0b9d..9b1d2aa38 100644
--- a/pkg/rpc/base/base.pb.go
+++ b/pkg/rpc/base/base.pb.go
@@ -60,6 +60,7 @@ const (
 	Code_ClientPieceDownloadFail Code = 4005
 	Code_ClientRequestLimitFail  Code = 4006
 	Code_ClientConnectionError   Code = 4007
+	Code_ClientBackSourceError   Code = 4008
 	Code_ClientPieceNotFound     Code = 4404
 	// scheduler response error 5000-5999
 	Code_SchedError                     Code = 5000
@@ -96,6 +97,7 @@ var (
 		4005: "ClientPieceDownloadFail",
 		4006: "ClientRequestLimitFail",
 		4007: "ClientConnectionError",
+		4008: "ClientBackSourceError",
 		4404: "ClientPieceNotFound",
 		5000: "SchedError",
 		5001: "SchedNeedBackSource",
@@ -126,6 +128,7 @@ var (
 		"ClientPieceDownloadFail":        4005,
 		"ClientRequestLimitFail":         4006,
 		"ClientConnectionError":          4007,
+		"ClientBackSourceError":          4008,
 		"ClientPieceNotFound":            4404,
 		"SchedError":                     5000,
 		"SchedNeedBackSource":            5001,
@@ -835,7 +838,7 @@ var file_pkg_rpc_base_base_proto_rawDesc = []byte{
 	0x68, 0x18, 0x07, 0x20, 0x01, 0x28, 0x03, 0x52, 0x0d, 0x63, 0x6f, 0x6e, 0x74, 0x65, 0x6e, 0x74,
 	0x4c, 0x65, 0x6e, 0x67, 0x74, 0x68, 0x12, 0x24, 0x0a, 0x0e, 0x70, 0x69, 0x65, 0x63, 0x65, 0x5f,
 	0x6d, 0x64, 0x35, 0x5f, 0x73, 0x69, 0x67, 0x6e, 0x18, 0x08, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0c,
-	0x70, 0x69, 0x65, 0x63, 0x65, 0x4d, 0x64, 0x35, 0x53, 0x69, 0x67, 0x6e, 0x2a, 0xa1, 0x05, 0x0a,
+	0x70, 0x69, 0x65, 0x63, 0x65, 0x4d, 0x64, 0x35, 0x53, 0x69, 0x67, 0x6e, 0x2a, 0xbd, 0x05, 0x0a,
 	0x04, 0x43, 0x6f, 0x64, 0x65, 0x12, 0x11, 0x0a, 0x0d, 0x58, 0x5f, 0x55, 0x4e, 0x53, 0x50, 0x45,
 	0x43, 0x49, 0x46, 0x49, 0x45, 0x44, 0x10, 0x00, 0x12, 0x0c, 0x0a, 0x07, 0x53, 0x75, 0x63, 0x63,
 	0x65, 0x73, 0x73, 0x10, 0xc8, 0x01, 0x12, 0x16, 0x0a, 0x11, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72,
@@ -859,33 +862,34 @@ var file_pkg_rpc_base_base_proto_rawDesc = []byte{
 	0x10, 0xa5, 0x1f, 0x12, 0x1b, 0x0a, 0x16, 0x43, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x52, 0x65, 0x71,
 	0x75, 0x65, 0x73, 0x74, 0x4c, 0x69, 0x6d, 0x69, 0x74, 0x46, 0x61, 0x69, 0x6c, 0x10, 0xa6, 0x1f,
 	0x12, 0x1a, 0x0a, 0x15, 0x43, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x43, 0x6f, 0x6e, 0x6e, 0x65, 0x63,
-	0x74, 0x69, 0x6f, 0x6e, 0x45, 0x72, 0x72, 0x6f, 0x72, 0x10, 0xa7, 0x1f, 0x12, 0x18, 0x0a, 0x13,
-	0x43, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x50, 0x69, 0x65, 0x63, 0x65, 0x4e, 0x6f, 0x74, 0x46, 0x6f,
-	0x75, 0x6e, 0x64, 0x10, 0xb4, 0x22, 0x12, 0x0f, 0x0a, 0x0a, 0x53, 0x63, 0x68, 0x65, 0x64, 0x45,
-	0x72, 0x72, 0x6f, 0x72, 0x10, 0x88, 0x27, 0x12, 0x18, 0x0a, 0x13, 0x53, 0x63, 0x68, 0x65, 0x64,
-	0x4e, 0x65, 0x65, 0x64, 0x42, 0x61, 0x63, 0x6b, 0x53, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x10, 0x89,
-	0x27, 0x12, 0x12, 0x0a, 0x0d, 0x53, 0x63, 0x68, 0x65, 0x64, 0x50, 0x65, 0x65, 0x72, 0x47, 0x6f,
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-	0x65, 0x72, 0x4e, 0x6f, 0x74, 0x46, 0x6f, 0x75, 0x6e, 0x64, 0x10, 0x8c, 0x27, 0x12, 0x23, 0x0a,
-	0x1e, 0x53, 0x63, 0x68, 0x65, 0x64, 0x50, 0x65, 0x65, 0x72, 0x50, 0x69, 0x65, 0x63, 0x65, 0x52,
-	0x65, 0x73, 0x75, 0x6c, 0x74, 0x52, 0x65, 0x70, 0x6f, 0x72, 0x74, 0x46, 0x61, 0x69, 0x6c, 0x10,
-	0x8d, 0x27, 0x12, 0x19, 0x0a, 0x14, 0x53, 0x63, 0x68, 0x65, 0x64, 0x54, 0x61, 0x73, 0x6b, 0x53,
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-	0x08, 0x43, 0x44, 0x4e, 0x45, 0x72, 0x72, 0x6f, 0x72, 0x10, 0xf0, 0x2e, 0x12, 0x18, 0x0a, 0x13,
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-	0x0a, 0x05, 0x50, 0x4c, 0x41, 0x49, 0x4e, 0x10, 0x00, 0x2a, 0x2c, 0x0a, 0x09, 0x53, 0x69, 0x7a,
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-	0x74, 0x6f, 0x33,
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+	0x43, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x42, 0x61, 0x63, 0x6b, 0x53, 0x6f, 0x75, 0x72, 0x63, 0x65,
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+	0x6e, 0x74, 0x50, 0x69, 0x65, 0x63, 0x65, 0x4e, 0x6f, 0x74, 0x46, 0x6f, 0x75, 0x6e, 0x64, 0x10,
+	0xb4, 0x22, 0x12, 0x0f, 0x0a, 0x0a, 0x53, 0x63, 0x68, 0x65, 0x64, 0x45, 0x72, 0x72, 0x6f, 0x72,
+	0x10, 0x88, 0x27, 0x12, 0x18, 0x0a, 0x13, 0x53, 0x63, 0x68, 0x65, 0x64, 0x4e, 0x65, 0x65, 0x64,
+	0x42, 0x61, 0x63, 0x6b, 0x53, 0x6f, 0x75, 0x72, 0x63, 0x65, 0x10, 0x89, 0x27, 0x12, 0x12, 0x0a,
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+	0x27, 0x12, 0x16, 0x0a, 0x11, 0x53, 0x63, 0x68, 0x65, 0x64, 0x50, 0x65, 0x65, 0x72, 0x4e, 0x6f,
+	0x74, 0x46, 0x6f, 0x75, 0x6e, 0x64, 0x10, 0x8c, 0x27, 0x12, 0x23, 0x0a, 0x1e, 0x53, 0x63, 0x68,
+	0x65, 0x64, 0x50, 0x65, 0x65, 0x72, 0x50, 0x69, 0x65, 0x63, 0x65, 0x52, 0x65, 0x73, 0x75, 0x6c,
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+	0x45, 0x72, 0x72, 0x6f, 0x72, 0x10, 0xf0, 0x2e, 0x12, 0x18, 0x0a, 0x13, 0x43, 0x44, 0x4e, 0x54,
+	0x61, 0x73, 0x6b, 0x52, 0x65, 0x67, 0x69, 0x73, 0x74, 0x72, 0x79, 0x46, 0x61, 0x69, 0x6c, 0x10,
+	0xf1, 0x2e, 0x12, 0x18, 0x0a, 0x13, 0x43, 0x44, 0x4e, 0x54, 0x61, 0x73, 0x6b, 0x44, 0x6f, 0x77,
+	0x6e, 0x6c, 0x6f, 0x61, 0x64, 0x46, 0x61, 0x69, 0x6c, 0x10, 0xf2, 0x2e, 0x12, 0x14, 0x0a, 0x0f,
+	0x43, 0x44, 0x4e, 0x54, 0x61, 0x73, 0x6b, 0x4e, 0x6f, 0x74, 0x46, 0x6f, 0x75, 0x6e, 0x64, 0x10,
+	0x84, 0x32, 0x12, 0x18, 0x0a, 0x13, 0x49, 0x6e, 0x76, 0x61, 0x6c, 0x69, 0x64, 0x52, 0x65, 0x73,
+	0x6f, 0x75, 0x72, 0x63, 0x65, 0x54, 0x79, 0x70, 0x65, 0x10, 0xd9, 0x36, 0x2a, 0x17, 0x0a, 0x0a,
+	0x50, 0x69, 0x65, 0x63, 0x65, 0x53, 0x74, 0x79, 0x6c, 0x65, 0x12, 0x09, 0x0a, 0x05, 0x50, 0x4c,
+	0x41, 0x49, 0x4e, 0x10, 0x00, 0x2a, 0x2c, 0x0a, 0x09, 0x53, 0x69, 0x7a, 0x65, 0x53, 0x63, 0x6f,
+	0x70, 0x65, 0x12, 0x0a, 0x0a, 0x06, 0x4e, 0x4f, 0x52, 0x4d, 0x41, 0x4c, 0x10, 0x00, 0x12, 0x09,
+	0x0a, 0x05, 0x53, 0x4d, 0x41, 0x4c, 0x4c, 0x10, 0x01, 0x12, 0x08, 0x0a, 0x04, 0x54, 0x49, 0x4e,
+	0x59, 0x10, 0x02, 0x42, 0x22, 0x5a, 0x20, 0x64, 0x37, 0x79, 0x2e, 0x69, 0x6f, 0x2f, 0x64, 0x72,
+	0x61, 0x67, 0x6f, 0x6e, 0x66, 0x6c, 0x79, 0x2f, 0x76, 0x32, 0x2f, 0x70, 0x6b, 0x67, 0x2f, 0x72,
+	0x70, 0x63, 0x2f, 0x62, 0x61, 0x73, 0x65, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (
diff --git a/pkg/rpc/base/base.proto b/pkg/rpc/base/base.proto
index cce63b42e..a5e4df2f8 100644
--- a/pkg/rpc/base/base.proto
+++ b/pkg/rpc/base/base.proto
@@ -46,6 +46,7 @@ enum Code{
   ClientPieceDownloadFail = 4005;
   ClientRequestLimitFail = 4006;
   ClientConnectionError = 4007;
+  ClientBackSourceError = 4008;
   ClientPieceNotFound = 4404;
 
   // scheduler response error 5000-5999