diff --git a/transport/cache.go b/transport/cache.go
index 561c92c1..da22cdee 100644
--- a/transport/cache.go
+++ b/transport/cache.go
@@ -88,5 +88,5 @@ func tlsConfigKey(c *Config) (string, error) {
 		return "", err
 	}
 	// Only include the things that actually affect the tls.Config
-	return fmt.Sprintf("%v/%x/%x/%x", c.TLS.Insecure, c.TLS.CAData, c.TLS.CertData, c.TLS.KeyData), nil
+	return fmt.Sprintf("%v/%x/%x/%x/%v", c.TLS.Insecure, c.TLS.CAData, c.TLS.CertData, c.TLS.KeyData, c.TLS.ServerName), nil
 }
diff --git a/transport/cache_test.go b/transport/cache_test.go
index eb9624d7..81f428de 100644
--- a/transport/cache_test.go
+++ b/transport/cache_test.go
@@ -62,6 +62,20 @@ func TestTLSConfigKey(t *testing.T) {
 				KeyData:  []byte{1},
 			},
 		},
+		"cert 1, key 1, servername 1": {
+			TLS: TLSConfig{
+				CertData:   []byte{1},
+				KeyData:    []byte{1},
+				ServerName: "1",
+			},
+		},
+		"cert 1, key 1, servername 2": {
+			TLS: TLSConfig{
+				CertData:   []byte{1},
+				KeyData:    []byte{1},
+				ServerName: "2",
+			},
+		},
 		"cert 1, key 2": {
 			TLS: TLSConfig{
 				CertData: []byte{1},