diff --git a/config.go b/config.go
index 63c7f6a..c7ad161 100644
--- a/config.go
+++ b/config.go
@@ -82,6 +82,10 @@ const (
 	endpointPrefixQUIC  = "quic://"
 	endpointPrefixH3    = "h3://"
 	endpointPrefixSdns  = "sdns://"
+
+	rebootstrapNotStarted = 0
+	rebootstrapStarted    = 1
+	rebootstrapInProgress = 2
 )
 
 var (
@@ -270,7 +274,7 @@ type UpstreamConfig struct {
 	Discoverable *bool `mapstructure:"discoverable" toml:"discoverable"`
 
 	g                  singleflight.Group
-	rebootstrap        atomic.Bool
+	rebootstrap        atomic.Int64
 	bootstrapIPs       []string
 	bootstrapIPs4      []string
 	bootstrapIPs6      []string
@@ -511,7 +515,7 @@ func (uc *UpstreamConfig) ReBootstrap(ctx context.Context) {
 		return
 	}
 	_, _, _ = uc.g.Do("ReBootstrap", func() (any, error) {
-		if uc.rebootstrap.CompareAndSwap(false, true) {
+		if uc.rebootstrap.CompareAndSwap(rebootstrapNotStarted, rebootstrapStarted) {
 			logger := LoggerFromCtx(ctx)
 			Log(ctx, logger.Debug(), "Re-bootstrapping upstream: %s", uc.Name)
 		}
@@ -557,8 +561,10 @@ func (uc *UpstreamConfig) ensureSetupTransport(ctx context.Context) {
 	uc.transportOnce.Do(func() {
 		uc.SetupTransport(ctx)
 	})
-	if uc.rebootstrap.CompareAndSwap(true, false) {
+
+	if uc.rebootstrap.CompareAndSwap(rebootstrapStarted, rebootstrapInProgress) {
 		uc.SetupTransport(ctx)
+		uc.rebootstrap.Store(rebootstrapNotStarted)
 	}
 }
 
diff --git a/config_internal_test.go b/config_internal_test.go
index 0e7f3bb..24f85b6 100644
--- a/config_internal_test.go
+++ b/config_internal_test.go
@@ -3,6 +3,7 @@ package ctrld
 import (
 	"context"
 	"net/url"
+	"sync"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -506,6 +507,52 @@ func TestUpstreamConfig_IsDiscoverable(t *testing.T) {
 	}
 }
 
+func TestRebootstrapRace(t *testing.T) {
+	uc := &UpstreamConfig{
+		Name:         "test-doh",
+		Type:         ResolverTypeDOH,
+		Endpoint:     "https://example.com/dns-query",
+		Domain:       "example.com",
+		bootstrapIPs: []string{"1.1.1.1", "1.0.0.1"},
+	}
+
+	ctx := LoggerCtx(context.Background(), NopLogger)
+
+	uc.SetupTransport(ctx)
+
+	if uc.transport == nil {
+		t.Fatal("initial transport should be set")
+	}
+
+	const goroutines = 100
+
+	uc.ReBootstrap(ctx)
+
+	started := make(chan struct{})
+	go func() {
+		close(started)
+		for {
+			switch uc.rebootstrap.Load() {
+			case rebootstrapStarted, rebootstrapInProgress:
+				uc.ReBootstrap(ctx)
+			default:
+				return
+			}
+		}
+	}()
+
+	<-started
+
+	var wg sync.WaitGroup
+	for range goroutines {
+		wg.Go(func() {
+			uc.ensureSetupTransport(ctx)
+		})
+	}
+
+	wg.Wait()
+}
+
 func ptrBool(b bool) *bool {
 	return &b
 }