diff --git a/inc/FileLogger.h b/inc/FileLogger.h
index 187863b..ee0c6ca 100644
--- a/inc/FileLogger.h
+++ b/inc/FileLogger.h
@@ -1,17 +1,13 @@
 //
 // Created by lukas on 05.05.19.
 //
+
 #pragma once
 
 #include <string>
+
 class FileLogger {
 public:
-    /**
-     * log messages to logfile
-     * @param text message
-     */
-    void logToLogfile(std::string text);
-
     /**
      * safe ip to temp file
      * @param ip ip address to save
diff --git a/inc/IPRefresher.h b/inc/IPRefresher.h
index 7dcaf9c..c3e4b03 100644
--- a/inc/IPRefresher.h
+++ b/inc/IPRefresher.h
@@ -12,5 +12,11 @@ public:
     void checkIPAdress(bool force);
 
     IPRefresher();
+
+    /**
+     * start the service in loop mode
+     * every 5 minutes the ip is checked an refreshed (needed for .service)
+     * @param loop true->loopmode on
+     */
     explicit IPRefresher(bool loop);
 };
diff --git a/inc/Logger.h b/inc/Logger.h
index 2e8b042..9bfc56a 100644
--- a/inc/Logger.h
+++ b/inc/Logger.h
@@ -13,7 +13,7 @@ public:
     static void warning(std::string message);
     static void error(std::string message);
 
-    static void log(std::string &message, int level);
+    static void log(const std::string &message, int level);
 
     static const int Debug;
     static const int Message;
diff --git a/src/Credentials.cpp b/src/Credentials.cpp
index b944d3a..c1c124d 100644
--- a/src/Credentials.cpp
+++ b/src/Credentials.cpp
@@ -48,5 +48,6 @@ bool Credentials::readCredentials() {
             std::cerr << "No '" << nfex.getPath() << "' setting in configuration file." << std::endl;
         }
     }
+    // check if needed values aren't empty
     return !(Credentials::dynuapikey.empty() || Credentials::domainid.empty() || Credentials::domainname.empty());
 }
diff --git a/src/FileLogger.cpp b/src/FileLogger.cpp
index 96c64d0..79b1a5d 100644
--- a/src/FileLogger.cpp
+++ b/src/FileLogger.cpp
@@ -3,9 +3,7 @@
 //
 
 #include <fstream>
-#include <ctime>
 #include <iostream>
-#include <sstream>
 
 #include "FileLogger.h"
 
@@ -28,22 +26,3 @@ std::string FileLogger::readip() {
 
     return ip;
 }
-
-void FileLogger::logToLogfile(std::string text) {
-    std::ofstream out;
-    out.open("dynurefresher.log", std::ios::out | std::ios::app);
-
-
-    std::time_t t = std::time(0);   // get time now
-    std::tm *now = std::localtime(&t);
-
-    std::stringstream logline;
-
-    logline << "[ " << (now->tm_year + 1900) << '-' << (now->tm_mon + 1) << '-' << now->tm_mday
-            << "_" << now->tm_hour << ":" << now->tm_min << ":" << now->tm_sec << " ] " << '\t' << text << std::endl;
-
-
-    out << logline.str();
-
-    out.close();
-}
diff --git a/src/IPRefresher.cpp b/src/IPRefresher.cpp
index 6c22b99..c031ba6 100644
--- a/src/IPRefresher.cpp
+++ b/src/IPRefresher.cpp
@@ -24,16 +24,13 @@ void IPRefresher::checkIPAdress(bool force) {
 
     if (ip.empty()) {
         //no internet connection (or other error)
-        logger.logToLogfile("[WARNING] no internet connection");
         Logger::warning("no internet connection");
     } else {
         std::string oldip = logger.readip();
 
         if (oldip == ip && !force) {
             Logger::message("no change -- ip: " + ip);
-            logger.logToLogfile(" [INFO] no change -- ip: " + ip);
         } else {
-            logger.logToLogfile(" [INFO] ip changed! -- from :" + oldip + "to: " + ip);
             Logger::message("ip changed! -- from :" + oldip + "to: " + ip);
 
             DynuAPI dynu;
@@ -45,7 +42,6 @@ void IPRefresher::checkIPAdress(bool force) {
                 tele.sendMessage(oldip + " moved to " + ip);
             } else {
                 //error
-                logger.logToLogfile(" [ERROR] failed to write ip to dynu api!");
                 Logger::error("failed to write ip to dynu api!");
             }
 
@@ -54,9 +50,7 @@ void IPRefresher::checkIPAdress(bool force) {
     }
 }
 
-IPRefresher::IPRefresher() {
-    // default constructor
-}
+IPRefresher::IPRefresher() = default;
 
 IPRefresher::IPRefresher(bool loop) {
     if (Credentials::readCredentials()) {
diff --git a/src/Logger.cpp b/src/Logger.cpp
index c6f11ff..5653cb3 100644
--- a/src/Logger.cpp
+++ b/src/Logger.cpp
@@ -13,23 +13,23 @@ const int Logger::Debug = 2;
 const int Logger::Message = 3;
 const int Logger::Error = 4;
 
-void Logger::debug(std::string message) {
+void Logger::debug(const std::string message) {
     log(message, Logger::Debug);
 }
 
-void Logger::message(std::string message) {
+void Logger::message(const std::string message) {
     log(message, Logger::Message);
 }
 
-void Logger::warning(std::string message) {
+void Logger::warning(const std::string message) {
     log(message, Logger::Warning);
 }
 
-void Logger::error(std::string message) {
+void Logger::error(const std::string message) {
     log(message, Logger::Error);
 }
 
-void Logger::log(std::string &message, int level) {
+void Logger::log(const std::string &message, int level) {
     std::stringstream out;
     out << "[";
     switch (level) {