diff --git a/CMakeLists.txt b/CMakeLists.txt
index c10cee9..71cc012 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,16 +10,16 @@
 cmake_minimum_required(VERSION 3.13)
 project(iprefresher DESCRIPTION "Dynu ip refresher")
 
-set(CMAKE_CXX_STANDARD 17)
+SET(CMAKE_CXX_STANDARD 17)
 
-set(CMAKE_BUILD_TYPE Release) # manually set build type (Release / Debug)
-set(LIB_METHOD STATIC) #SHARED / STATIC
-set(PROJECT_VERSION 1.3.1-dev)
+SET(CMAKE_BUILD_TYPE Release) # manually SET build type (Release / Debug)
+SET(LIB_METHOD STATIC) #SHARED / STATIC
+SET(PROJECT_VERSION 1.3.1-dev)
 option(BUILD_DOC "Build documentation" ON)
 
-set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
-set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
-set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+SET(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+SET(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
+SET(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
 # config libs
 message(STATUS "Config of Libraries")
@@ -59,6 +59,17 @@ FILE(WRITE ${CMAKE_SOURCE_DIR}/inc/Version.h
         "\#pragma once\n#include <string>\nnamespace Version {\n  const std::string VERSION = \"${PROJECT_VERSION}\";\n}"
         )
 
+#read sample config
+FILE(READ ${CMAKE_SOURCE_DIR}/config/iprefresher.cfg SAMPLECONFIG)
+# generate post script for checking if configuration already exists
+FILE(WRITE ${CMAKE_SOURCE_DIR}/postinstall.sh
+        "#!/bin/bash
+if [ ! -f /etc/iprefresher.cfg ]; then
+    cat > /etc/iprefresher.cfg <<- EOM
+${SAMPLECONFIG}EOM
+fi"
+        )
+
 add_library(api ${LIB_METHOD}
         src/api/API.cpp
 
@@ -75,7 +86,7 @@ add_library(logger ${LIB_METHOD}
         )
 
 
-set(SOURCE
+SET(SOURCE
         src/main.cpp
         src/IPRefresher.cpp
         src/Config.cpp)
@@ -86,16 +97,9 @@ add_executable(iprefresher ${SOURCE})
 target_link_libraries(iprefresher api logger ${CURL_LIBRARIES} config++)
 
 # INSTALL to SYSTEM #
-set(CMAKE_INSTALL_PREFIX "/")
+SET(CMAKE_INSTALL_PREFIX "/")
 # install binaries
 install(TARGETS iprefresher DESTINATION usr/bin)
-# install config file if it doesn't exist
-install(CODE "MESSAGE(STATUS \"Copy iprefresher.cfg to ${CMAKE_INSTALL_PREFIX}etc/iprefresher.cfg\")
-    IF (NOT EXISTS ${CMAKE_INSTALL_PREFIX}etc/iprefresher.cfg)
-        EXECUTE_PROCESS(COMMAND ${CMAKE_COMMAND} -E copy
-                ${CMAKE_CURRENT_SOURCE_DIR}/config/iprefresher.cfg
-                ${CMAKE_INSTALL_PREFIX}etc/iprefresher.cfg)
-    ENDIF (NOT EXISTS ${CMAKE_INSTALL_PREFIX}etc/iprefresher.cfg)")
 # install systemd service and enable it
 install(FILES service/iprefresher.service DESTINATION lib/systemd/system)
 
@@ -104,7 +108,7 @@ IF (UNIX)
     message(STATUS "config of Package build")
     SET(CPACK_DEB_COMPONENT_INSTALL 1)
     SET(CPACK_OUTPUT_FILE_PREFIX packages)
-    set(CPACK_PACKAGING_INSTALL_PREFIX "/") # no prefix for package structure
+    SET(CPACK_PACKAGING_INSTALL_PREFIX "/") # no prefix for package structure
 
     FIND_PROGRAM(RPMBUILD_EXECUTABLE rpmbuild)
     FIND_PROGRAM(DEB_EXECUTABLE dpkg)
@@ -114,8 +118,9 @@ IF (UNIX)
     #check if rpm build is possible
     if (NOT ${RPMBUILD_EXECUTABLE} STREQUAL "RPMBUILD_EXECUTABLE-NOTFOUND")
         message(STATUS "found rpm build executeable --> able to build rpm")
-        set(CPACK_GENERATOR "${CPACK_GENERATOR};RPM")
-        set(CPACK_RPM_EXCLUDE_FROM_AUTO_FILELIST_ADDITION "/lib/systemd/system" "/lib/systemd" "/lib" "/usr/local/bin" "/usr/local") # --> needed to not override existing folders
+        SET(CPACK_GENERATOR "${CPACK_GENERATOR};RPM")
+        SET(CPACK_RPM_POST_INSTALL_SCRIPT_FILE "${CMAKE_CURRENT_SOURCE_DIR}/postinstall.sh")
+        SET(CPACK_RPM_EXCLUDE_FROM_AUTO_FILELIST_ADDITION "/lib/systemd/system" "/lib/systemd" "/lib" "/usr/local/bin" "/usr/local") # --> needed to not override existing folders
     else (NOT ${RPMBUILD_EXECUTABLE} STREQUAL "RPMBUILD_EXECUTABLE-NOTFOUND")
         message(STATUS "not found rpm build tools --> not building rpm")
     endif (NOT ${RPMBUILD_EXECUTABLE} STREQUAL "RPMBUILD_EXECUTABLE-NOTFOUND")
@@ -123,7 +128,8 @@ IF (UNIX)
     #check if deb build is possible
     if (NOT ${DEB_EXECUTABLE} STREQUAL "DEB_EXECUTABLE-NOTFOUND")
         message(STATUS "found deb build tools --> able to build deb")
-        set(CPACK_GENERATOR "${CPACK_GENERATOR};DEB")
+        SET(CPACK_GENERATOR "${CPACK_GENERATOR};DEB")
+        set(CPACK_DEBIAN_PACKAGE_CONTROL_EXTRA "${CMAKE_CURRENT_SOURCE_DIR}/postinstall.sh")
     else (NOT ${DEB_EXECUTABLE} STREQUAL "DEB_EXECUTABLE-NOTFOUND")
         message(STATUS "not found  deb build tools --> not building deb")
     endif (NOT ${DEB_EXECUTABLE} STREQUAL "DEB_EXECUTABLE-NOTFOUND")
@@ -139,7 +145,8 @@ IF (UNIX)
     SET(CPACK_SOURCE_PACKAGE_FILE_NAME "${CMAKE_PROJECT_NAME}-${PROJECT_VERSION}")
     SET(CPACK_PACKAGE_CONTACT "Lukas Heiligenbrunner <lukas.heiligenbrunner@gmail.com>")
     SET(CPACK_PACKAGE_SECTION "games")
-    set(CPACK_PACKAGE_DEPENDS "libcurl (>= 7.0.0-1), libconfig (>= 1.5.0)")
+    SET(CPACK_PACKAGE_DEPENDS "libcurl (>= 7.0.0-1), libconfig (>= 1.5.0)")
+    SET(CPACK_RPM_POST_INSTALL_SCRIPT_FILE "${CMAKE_CURRENT_SOURCE_DIR}/postinstall.sh")
 
     INCLUDE(CPack)
 
@@ -155,9 +162,9 @@ if (BUILD_DOC)
     message(STATUS "config of DOxygen build")
     find_package(Doxygen)
     if (DOXYGEN_FOUND)
-        # set input and output files
-        set(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/docs/Doxyfile.in)
-        set(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
+        # SET input and output files
+        SET(DOXYGEN_IN ${CMAKE_CURRENT_SOURCE_DIR}/docs/Doxyfile.in)
+        SET(DOXYGEN_OUT ${CMAKE_CURRENT_BINARY_DIR}/Doxyfile)
 
         # request to configure the file
         configure_file(${DOXYGEN_IN} ${DOXYGEN_OUT} @ONLY)