diff --git a/go-backend/internal/http/handler/tunnel_probe_target.go b/go-backend/internal/http/handler/tunnel_probe_target.go
index 80af291..be8e234 100644
--- a/go-backend/internal/http/handler/tunnel_probe_target.go
+++ b/go-backend/internal/http/handler/tunnel_probe_target.go
@@ -38,13 +38,44 @@ func normalizeTunnelProbeTarget(host string, port int) (tunnelProbeTarget, bool,
 	if port <= 0 || port > 65535 {
 		return tunnelProbeTarget{}, false, errors.New("测试目标端口必须是 1-65535")
 	}
-	if strings.Contains(host, "://") || strings.ContainsAny(host, "/?#") || strings.ContainsAny(host, " \t\r\n") {
+	if strings.Contains(host, "://") || isTunnelProbeTargetSchemeLikeHost(host) || strings.ContainsAny(host, "/?#") || strings.ContainsAny(host, " \t\r\n") {
 		return tunnelProbeTarget{}, false, errors.New("测试目标 Host 不能包含协议或路径")
 	}
 
 	return tunnelProbeTarget{Host: host, Port: port}, true, nil
 }
 
+func isTunnelProbeTargetSchemeLikeHost(host string) bool {
+	if _, err := netip.ParseAddr(host); err == nil {
+		return false
+	}
+
+	colon := strings.IndexByte(host, ':')
+	if colon <= 0 {
+		return false
+	}
+	for i, r := range host[:colon] {
+		if i == 0 {
+			if !isASCIILetter(r) {
+				return false
+			}
+			continue
+		}
+		if !isASCIILetter(r) && !isASCIIDigit(r) && r != '+' && r != '-' && r != '.' {
+			return false
+		}
+	}
+	return true
+}
+
+func isASCIILetter(r rune) bool {
+	return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z')
+}
+
+func isASCIIDigit(r rune) bool {
+	return r >= '0' && r <= '9'
+}
+
 func parseTunnelProbeTargetFromRequest(req map[string]interface{}) (tunnelProbeTarget, bool, error) {
 	if req == nil {
 		return defaultTunnelProbeTarget(), false, nil
diff --git a/go-backend/internal/http/handler/tunnel_probe_target_test.go b/go-backend/internal/http/handler/tunnel_probe_target_test.go
index a39a2ed..df0ecc9 100644
--- a/go-backend/internal/http/handler/tunnel_probe_target_test.go
+++ b/go-backend/internal/http/handler/tunnel_probe_target_test.go
@@ -54,6 +54,24 @@ func TestNormalizeTunnelProbeTargetRejectsPartialAndInvalidInputs(t *testing.T)
 	}
 }
 
+func TestNormalizeTunnelProbeTargetRejectsSchemePrefixButAllowsIPv6(t *testing.T) {
+	for _, host := range []string{"https:example.com", "mailto:ops@example.com"} {
+		if _, _, err := normalizeTunnelProbeTarget(host, 443); err == nil {
+			t.Fatalf("expected scheme-like host %q to be rejected", host)
+		}
+	}
+
+	for _, host := range []string{"2001:db8::1", "[2001:db8::1]"} {
+		target, configured, err := normalizeTunnelProbeTarget(host, 443)
+		if err != nil {
+			t.Fatalf("expected IPv6 host %q to be accepted: %v", host, err)
+		}
+		if !configured || target.Host != "2001:db8::1" {
+			t.Fatalf("unexpected IPv6 normalization for %q: %+v configured=%v", host, target, configured)
+		}
+	}
+}
+
 func TestParseTunnelProbeTargetFromRequest(t *testing.T) {
 	req := map[string]interface{}{
 		"probeTargetHost": "speed.example.com",