diff --git a/cmd/main.go b/cmd/main.go
index d832cbc5..9be3585b 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -157,11 +157,16 @@ func loadConfigWithLogger(logger *zap.Logger, configFile, adapterName string) ([
 		}
 	}
 
-	// as a special case, if a config file called "Caddyfile" was
-	// specified, and no adapter is specified, assume caddyfile adapter
-	// for convenience
-	if strings.HasPrefix(filepath.Base(configFile), "Caddyfile") &&
-		filepath.Ext(configFile) != ".json" &&
+	// as a special case, if a config file starts with "caddyfile" or
+	// has a ".caddyfile" extension, and no adapter is specified, and
+	// no adapter module name matches the extension, assume
+	// caddyfile adapter for convenience
+	baseConfig := strings.ToLower(filepath.Base(configFile))
+	baseConfigExt := filepath.Ext(baseConfig)
+	if (strings.HasPrefix(baseConfig, "caddyfile") ||
+		strings.HasSuffix(baseConfig, ".caddyfile")) &&
+		caddyconfig.GetAdapter(baseConfigExt[1:]) == nil &&
+		baseConfigExt != ".json" &&
 		adapterName == "" {
 		adapterName = "caddyfile"
 	}