diff --git a/Documentation/Getting-Started/Building-MaxScale-from-Source-Code.md b/Documentation/Getting-Started/Building-MaxScale-from-Source-Code.md
index 99baf3004..75870071e 100644
--- a/Documentation/Getting-Started/Building-MaxScale-from-Source-Code.md
+++ b/Documentation/Getting-Started/Building-MaxScale-from-Source-Code.md
@@ -12,6 +12,8 @@ You will need a number of tools and libraries in order to achieve this.
 
 * libedit 2.11 or later (used by the MaxAdmin tool)
 
+* Bison and Flex
+
 # Obtaining MariaDB packages
 
 MaxScale requires the server and the development packages for the MariaDB server. Either the 10.0 or the 5.5 version of the MariaDB server can be used. You can obtain these by following the instructions on the MariaDB.org site: [https://downloads.mariadb.org/](https://downloads.mariadb.org/)
@@ -27,7 +29,7 @@ The full list of dependencies for the most common distributions is provided in t
 You will need to install all of the following packages for all versions of RHEL and CentOS.
 
 ```
-gcc gcc-c++ ncurses-devel bison glibc-devel cmake libgcc perl make libtool \
+gcc gcc-c++ ncurses-devel bison flex glibc-devel cmake libgcc perl make libtool \
     openssl-devel libaio libaio-devel librabbitmq-devel libcurl-devel pcre-devel
 ```
 
@@ -61,7 +63,7 @@ MariaDB-devel MariaDB-server
 These packages are required on all versions of Ubuntu and Debian.
 
 ```
-	build-essential libssl-dev libaio-dev ncurses-dev bison \
+	build-essential libssl-dev libaio-dev ncurses-dev bison flex \
 	cmake perl libtool librabbitmq-dev libcurl-dev libpcre3-dev
 ```
 
diff --git a/server/modules/filter/dbfwfilter/CMakeLists.txt b/server/modules/filter/dbfwfilter/CMakeLists.txt
index 8c34f5b5d..8c529aa6c 100644
--- a/server/modules/filter/dbfwfilter/CMakeLists.txt
+++ b/server/modules/filter/dbfwfilter/CMakeLists.txt
@@ -10,4 +10,6 @@ if(BISON_FOUND AND FLEX_FOUND)
   target_link_libraries(dbfwfilter maxscale-common)
   set_target_properties(dbfwfilter PROPERTIES VERSION "1.0.0")
   install(TARGETS dbfwfilter DESTINATION ${MAXSCALE_LIBDIR})
+else()
+    mesage(FATAL_ERROR "Could not find Bison or Flex: ${BISON_EXECUTABLE} ${FLEX_EXECUTABLE}")
 endif()