diff --git a/weed/command/master.go b/weed/command/master.go
index 2a7511fbf..565c9cc58 100644
--- a/weed/command/master.go
+++ b/weed/command/master.go
@@ -4,9 +4,11 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"net"
 	"net/http"
 	"os"
 	"path"
+	"strconv"
 	"strings"
 	"time"
 
@@ -338,8 +340,16 @@ func checkPeers(masterIp string, masterPort int, masterGrpcPort int, peers strin
 	}
 
 	peers = strings.TrimSpace(peers)
-
-	cleanedPeers = pb.ServerAddresses(peers).ToAddresses()
+	seenPeers := make(map[string]struct{})
+	for _, peer := range pb.ServerAddresses(peers).ToAddresses() {
+		normalizedPeer := normalizeMasterPeerAddress(peer, masterAddress)
+		key := string(normalizedPeer)
+		if _, found := seenPeers[key]; found {
+			continue
+		}
+		seenPeers[key] = struct{}{}
+		cleanedPeers = append(cleanedPeers, normalizedPeer)
+	}
 
 	hasSelf := false
 	for _, peer := range cleanedPeers {
@@ -358,14 +368,31 @@ func checkPeers(masterIp string, masterPort int, masterGrpcPort int, peers strin
 	return
 }
 
+func normalizeMasterPeerAddress(peer pb.ServerAddress, self pb.ServerAddress) pb.ServerAddress {
+	if peer.ToHttpAddress() == self.ToHttpAddress() {
+		return self
+	}
+
+	_, grpcPort, err := net.SplitHostPort(peer.ToGrpcAddress())
+	if err != nil {
+		return peer
+	}
+	grpcPortValue, err := strconv.Atoi(grpcPort)
+	if err != nil {
+		return peer
+	}
+
+	return pb.NewServerAddressWithGrpcPort(peer.ToHttpAddress(), grpcPortValue)
+}
+
 func isTheFirstOne(self pb.ServerAddress, peers []pb.ServerAddress) bool {
 	slices.SortFunc(peers, func(a, b pb.ServerAddress) int {
-		return strings.Compare(string(a), string(b))
+		return strings.Compare(a.ToHttpAddress(), b.ToHttpAddress())
 	})
 	if len(peers) <= 0 {
 		return true
 	}
-	return self == peers[0]
+	return self.ToHttpAddress() == peers[0].ToHttpAddress()
 }
 
 func (m *MasterOptions) toMasterOption(whiteList []string) *weed_server.MasterOption {
diff --git a/weed/command/master_test.go b/weed/command/master_test.go
new file mode 100644
index 000000000..b92254606
--- /dev/null
+++ b/weed/command/master_test.go
@@ -0,0 +1,66 @@
+package command
+
+import (
+	"testing"
+
+	"github.com/seaweedfs/seaweedfs/weed/pb"
+)
+
+func TestIsTheFirstOneIgnoresGrpcPort(t *testing.T) {
+	self := pb.ServerAddress("127.0.0.1:9000.19000")
+	peers := []pb.ServerAddress{
+		"127.0.0.1:9000",
+		"127.0.0.1:9002.19002",
+		"127.0.0.1:9003.19003",
+	}
+
+	if !isTheFirstOne(self, peers) {
+		t.Fatalf("expected first peer match by HTTP address between %q and %+v", self, peers)
+	}
+}
+
+func TestCheckPeersAddsSelfWhenGrpcPortMismatches(t *testing.T) {
+	self, peers := checkPeers("127.0.0.1", 9000, 19000, "127.0.0.1:9002,127.0.0.1:9003")
+
+	found := false
+	for _, peer := range peers {
+		if peer.ToHttpAddress() == self.ToHttpAddress() {
+			found = true
+			break
+		}
+	}
+	if !found {
+		t.Fatalf("expected peers %+v to contain self %s by HTTP address", peers, self)
+	}
+}
+
+func TestCheckPeersCanonicalizesSelfEntry(t *testing.T) {
+	self, peers := checkPeers("127.0.0.1", 9000, 19000, "127.0.0.1:9000,127.0.0.1:9002,127.0.0.1:9003")
+
+	for _, peer := range peers {
+		if peer.ToHttpAddress() == self.ToHttpAddress() && peer != self {
+			t.Fatalf("expected self peer to be canonicalized to %q, got %q", self, peer)
+		}
+	}
+}
+
+func TestCheckPeersDeduplicatesAliasPeers(t *testing.T) {
+	_, peers := checkPeers("127.0.0.1", 9000, 19000, "127.0.0.1:9002,127.0.0.1:9002.19002,127.0.0.1:9003")
+
+	if len(peers) != 3 {
+		t.Fatalf("expected 3 unique peers after normalization, got %d: %+v", len(peers), peers)
+	}
+
+	count9002 := 0
+	for _, peer := range peers {
+		if peer.ToHttpAddress() == "127.0.0.1:9002" {
+			count9002++
+			if string(peer) != "127.0.0.1:9002.19002" {
+				t.Fatalf("expected canonical peer 127.0.0.1:9002.19002, got %q", peer)
+			}
+		}
+	}
+	if count9002 != 1 {
+		t.Fatalf("expected one peer for 127.0.0.1:9002, got %d in %+v", count9002, peers)
+	}
+}