diff --git a/infra/conf/transport_internet.go b/infra/conf/transport_internet.go
index 0d1c5c1e..16fc499c 100644
--- a/infra/conf/transport_internet.go
+++ b/infra/conf/transport_internet.go
@@ -608,9 +608,11 @@ func (c *REALITYConfig) Build() (proto.Message, error) {
 		config.ServerNames = c.ServerNames
 		config.MaxTimeDiff = c.MaxTimeDiff
 
+		config.LimitFallbackUpload = new(reality.LimitFallback)
 		config.LimitFallbackUpload.BytesPerSec = c.LimitFbUploadRate
 		config.LimitFallbackUpload.BurstBytesPerSec = c.LimitFbUploadBurst
 		config.LimitFallbackUpload.AfterBytes = c.LimitFbUploadAfter
+		config.LimitFallbackDownload = new(reality.LimitFallback)
 		config.LimitFallbackDownload.BytesPerSec = c.LimitFbDownloadRate
 		config.LimitFallbackDownload.BurstBytesPerSec = c.LimitFbDownloadBurst
 		config.LimitFallbackDownload.AfterBytes = c.LimitFbDownloadAfter
diff --git a/transport/internet/reality/config.go b/transport/internet/reality/config.go
index 79bb69de..a776f351 100644
--- a/transport/internet/reality/config.go
+++ b/transport/internet/reality/config.go
@@ -31,13 +31,16 @@ func (c *Config) GetREALITYConfig() *reality.Config {
 		SessionTicketsDisabled: true,
 
 		KeyLogWriter: KeyLogWriterFromConfig(c),
-
-		LimitFbUploadRate:    c.LimitFallbackUpload.BytesPerSec,
-		LimitFbUploadBurst:   c.LimitFallbackUpload.BurstBytesPerSec,
-		LimitFbUploadAfter:   c.LimitFallbackUpload.AfterBytes,
-		LimitFbDownloadRate:  c.LimitFallbackDownload.BytesPerSec,
-		LimitFbDownloadBurst: c.LimitFallbackDownload.BurstBytesPerSec,
-		LimitFbDownloadAfter: c.LimitFallbackDownload.AfterBytes,
+	}
+	if c.LimitFallbackUpload != nil {
+		config.LimitFbUploadRate = c.LimitFallbackUpload.BytesPerSec
+		config.LimitFbUploadBurst = c.LimitFallbackUpload.BurstBytesPerSec
+		config.LimitFbUploadAfter = c.LimitFallbackUpload.AfterBytes
+	}
+	if c.LimitFallbackDownload != nil {
+		config.LimitFbDownloadRate = c.LimitFallbackDownload.BytesPerSec
+		config.LimitFbDownloadBurst = c.LimitFallbackDownload.BurstBytesPerSec
+		config.LimitFbDownloadAfter = c.LimitFallbackDownload.AfterBytes
 	}
 	config.ServerNames = make(map[string]bool)
 	for _, serverName := range c.ServerNames {