diff --git a/CMakeLists.txt b/CMakeLists.txt
index ec4fc25443..d717ef717a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -139,6 +139,8 @@ else ()
 endif ()
 option (jemalloc "Enables jemalloc for heap profiling" OFF)
 option (werr "treat warnings as errors" OFF)
+option (local_protobuf
+  "Force use of a local build of protobuf instead of system version." OFF)
 
 # this one is a string and therefore can't be an option
 set (san "" CACHE STRING "On gcc & clang, add sanitizer instrumentation")
@@ -612,10 +614,11 @@ set_target_properties(OpenSSL::SSL PROPERTIES
    build option
 #]=========================================================]
 find_package (ZLIB)
+set (has_zlib FALSE)
 if (TARGET ZLIB::ZLIB)
-  #target_link_libraries (OpenSSL::Crypto INTERFACE ZLIB::ZLIB)
   set_target_properties(OpenSSL::Crypto PROPERTIES
     INTERFACE_LINK_LIBRARIES ZLIB::ZLIB)
+  set (has_zlib TRUE)
 endif ()
 
 #[===================================================================[
@@ -924,13 +927,13 @@ set(sqlite_BINARY_DIR ${BINARY_DIR})
    NIH dep: soci
 #]===================================================================]
 
-set (lib_pre ${ep_lib_prefix})
-set (lib_post "")
+set (soci_lib_pre ${ep_lib_prefix})
+set (soci_lib_post "")
 if (WIN32)
   # for some reason soci on windows still prepends lib (non-standard)
-  set (lib_pre lib)
+  set (soci_lib_pre lib)
   # this version in the name might change if/when we change versions of soci
-  set (lib_post "_4_0")
+  set (soci_lib_post "_4_0")
 endif ()
 ExternalProject_Add (soci
   PREFIX ${nih_cache_path}
@@ -993,21 +996,21 @@ ExternalProject_Add (soci
     $<$<BOOL:${is_multiconfig}>:
       COMMAND
         ${CMAKE_COMMAND} -E copy
-        <BINARY_DIR>/lib/$<CONFIG>/${lib_pre}soci_core${lib_post}$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
-        <BINARY_DIR>/lib/$<CONFIG>/${lib_pre}soci_empty${lib_post}$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
-        <BINARY_DIR>/lib/$<CONFIG>/${lib_pre}soci_sqlite3${lib_post}$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
+        <BINARY_DIR>/lib/$<CONFIG>/${soci_lib_pre}soci_core${soci_lib_post}$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
+        <BINARY_DIR>/lib/$<CONFIG>/${soci_lib_pre}soci_empty${soci_lib_post}$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
+        <BINARY_DIR>/lib/$<CONFIG>/${soci_lib_pre}soci_sqlite3${soci_lib_post}$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
         <BINARY_DIR>/lib
       >
   TEST_COMMAND ""
   INSTALL_COMMAND ""
   DEPENDS sqlite3
   BUILD_BYPRODUCTS
-    <BINARY_DIR>/lib/${lib_pre}soci_core${lib_post}${ep_lib_suffix}
-    <BINARY_DIR>/lib/${lib_pre}soci_core${lib_post}_d${ep_lib_suffix}
-    <BINARY_DIR>/lib/${lib_pre}soci_empty${lib_post}${ep_lib_suffix}
-    <BINARY_DIR>/lib/${lib_pre}soci_empty${lib_post}_d${ep_lib_suffix}
-    <BINARY_DIR>/lib/${lib_pre}soci_sqlite3${lib_post}${ep_lib_suffix}
-    <BINARY_DIR>/lib/${lib_pre}soci_sqlite3${lib_post}_d${ep_lib_suffix}
+    <BINARY_DIR>/lib/${soci_lib_pre}soci_core${soci_lib_post}${ep_lib_suffix}
+    <BINARY_DIR>/lib/${soci_lib_pre}soci_core${soci_lib_post}_d${ep_lib_suffix}
+    <BINARY_DIR>/lib/${soci_lib_pre}soci_empty${soci_lib_post}${ep_lib_suffix}
+    <BINARY_DIR>/lib/${soci_lib_pre}soci_empty${soci_lib_post}_d${ep_lib_suffix}
+    <BINARY_DIR>/lib/${soci_lib_pre}soci_sqlite3${soci_lib_post}${ep_lib_suffix}
+    <BINARY_DIR>/lib/${soci_lib_pre}soci_sqlite3${soci_lib_post}_d${ep_lib_suffix}
 )
 ExternalProject_Get_Property (soci BINARY_DIR)
 ExternalProject_Get_Property (soci SOURCE_DIR)
@@ -1020,9 +1023,9 @@ foreach (_comp core empty sqlite3)
   add_library ("soci_${_comp}" STATIC IMPORTED GLOBAL)
   set_target_properties ("soci_${_comp}" PROPERTIES
     IMPORTED_LOCATION_DEBUG
-      ${BINARY_DIR}/lib/${lib_pre}soci_${_comp}${lib_post}_d${ep_lib_suffix}
+      ${BINARY_DIR}/lib/${soci_lib_pre}soci_${_comp}${soci_lib_post}_d${ep_lib_suffix}
     IMPORTED_LOCATION_RELEASE
-      ${BINARY_DIR}/lib/${lib_pre}soci_${_comp}${lib_post}${ep_lib_suffix}
+      ${BINARY_DIR}/lib/${soci_lib_pre}soci_${_comp}${soci_lib_post}${ep_lib_suffix}
     INTERFACE_INCLUDE_DIRECTORIES
       "${SOURCE_DIR}/include;${BINARY_DIR}/include")
   add_dependencies ("soci_${_comp}" soci) # something has to depend on the ExternalProject to trigger it
@@ -1189,35 +1192,103 @@ target_link_libraries (ripple_libs INTERFACE NIH::nudb)
 
 #[===================================================================[
    import protobuf (lib and compiler) and create a lib
-   from our proto message definitions. There is fallback
-   logic for windows that builds some version of the protobuf
-   core library from source and downloads the protoc compiler
-   if needed
+   from our proto message definitions. If the system protobuf
+   is not found, fallback on EP to download and build a version
+   from official source.
 #]===================================================================]
 
 if (static)
   set (Protobuf_USE_STATIC_LIBS ON)
 endif ()
 find_package (Protobuf)
-if (MSVC AND NOT TARGET protobuf::protoc)
-  find_program (my_protoc NAMES protoc)
-  if (NOT my_protoc)
-    message (WARNING "No protoc found -- downloading now")
-    file (DOWNLOAD
-      "https://ripple.github.io/Downloads/protoc/2.5.1/protoc.exe"
-      ${CMAKE_BINARY_DIR}/tools/protoc.exe
-      STATUS status
-      TIMEOUT 30)
-    list (GET status 0 status_code)
-    list (GET status 1 status_string)
-    if (NOT status_code EQUAL 0)
-      message (FATAL_ERROR "Failed to download protoc: ${status_string}")
-    endif ()
-    set (my_protoc ${CMAKE_BINARY_DIR}/tools/protoc.exe)
+if (local_protobuf OR NOT TARGET protobuf::libprotobuf)
+  message (STATUS "using local protobuf build.")
+  if (WIN32)
+    # protobuf prepends lib even on windows
+    set (pbuf_lib_pre "lib")
+  else ()
+    set (pbuf_lib_pre ${ep_lib_prefix})
+  endif ()
+  # for the external project build of protobuf, we currently ignore the
+  # static option and always build static libs here. This is consistent
+  # with our other EP builds. Dynamic libs in an EP would add complexity
+  # because we'd need to get them into the runtime path, and probably
+  # install them.
+  ExternalProject_Add (protobuf_src
+    PREFIX ${nih_cache_path}
+    GIT_REPOSITORY https://github.com/protocolbuffers/protobuf.git
+    GIT_TAG v3.6.1
+    SOURCE_SUBDIR cmake
+    CMAKE_ARGS
+      -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
+      -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
+      -Dprotobuf_BUILD_TESTS=OFF
+      -Dprotobuf_BUILD_EXAMPLES=OFF
+      -Dprotobuf_BUILD_PROTOC_BINARIES=ON
+      -Dprotobuf_MSVC_STATIC_RUNTIME=ON
+      -DBUILD_SHARED_LIBS=OFF
+      -Dprotobuf_BUILD_SHARED_LIBS=OFF
+      -DCMAKE_DEBUG_POSTFIX=_d
+      -Dprotobuf_DEBUG_POSTFIX=_d
+      -Dprotobuf_WITH_ZLIB=$<IF:$<BOOL:${has_zlib}>,ON,OFF>
+      $<$<BOOL:${CMAKE_VERBOSE_MAKEFILE}>:-DCMAKE_VERBOSE_MAKEFILE=ON>
+      $<$<NOT:$<BOOL:${is_multiconfig}>>:-DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}>
+      $<$<BOOL:${MSVC}>:
+	"-DCMAKE_CXX_FLAGS=-GR -Gd -fp:precise -FS -EHa -MP"
+      >
+    LOG_BUILD ON
+    LOG_CONFIGURE ON
+    BUILD_COMMAND
+      ${CMAKE_COMMAND}
+      --build .
+      --config $<CONFIG>
+      $<$<VERSION_GREATER_EQUAL:${CMAKE_VERSION},3.12>:--parallel$<$<BOOL:${is_xcode}>: ${num_procs}>>
+      $<$<BOOL:${is_multiconfig}>:
+        COMMAND
+          ${CMAKE_COMMAND} -E copy
+          <BINARY_DIR>/$<CONFIG>/${pbuf_lib_pre}protobuf$<$<CONFIG:Debug>:_d>${ep_lib_suffix}
+          <BINARY_DIR>
+        COMMAND
+          ${CMAKE_COMMAND} -E copy
+          <BINARY_DIR>/$<CONFIG>/protoc${CMAKE_EXECUTABLE_SUFFIX}
+          <BINARY_DIR>
+        >
+    TEST_COMMAND ""
+    INSTALL_COMMAND ""
+    BUILD_BYPRODUCTS
+      <BINARY_DIR>/${pbuf_lib_pre}protobuf${ep_lib_suffix}
+      <BINARY_DIR>/${pbuf_lib_pre}protobuf_d${ep_lib_suffix}
+      <BINARY_DIR>/protoc${CMAKE_EXECUTABLE_SUFFIX}
+  )
+  ExternalProject_Get_Property (protobuf_src BINARY_DIR)
+  ExternalProject_Get_Property (protobuf_src SOURCE_DIR)
+  ExternalProject_Get_Property (protobuf_src STAMP_DIR)
+  if (CMAKE_VERBOSE_MAKEFILE)
+    print_ep_logs (protobuf_src)
+  endif ()
+
+  if (NOT TARGET protobuf::libprotobuf)
+    add_library (protobuf::libprotobuf STATIC IMPORTED GLOBAL)
+  endif ()
+  file (MAKE_DIRECTORY ${SOURCE_DIR}/src)
+  set_target_properties (protobuf::libprotobuf PROPERTIES
+    IMPORTED_LOCATION_DEBUG
+      ${BINARY_DIR}/${pbuf_lib_pre}protobuf_d${ep_lib_suffix}
+    IMPORTED_LOCATION_RELEASE
+      ${BINARY_DIR}/${pbuf_lib_pre}protobuf${ep_lib_suffix}
+    INTERFACE_INCLUDE_DIRECTORIES
+      ${SOURCE_DIR}/src)
+  add_dependencies (protobuf::libprotobuf protobuf_src)
+  exclude_if_included (protobuf_src)
+  exclude_if_included (protobuf::libprotobuf)
+
+  if (NOT TARGET protobuf::protoc)
+    add_executable (protobuf::protoc IMPORTED)
+    exclude_if_included (protobuf::protoc)
   endif ()
-  add_executable (protobuf::protoc IMPORTED)
   set_target_properties (protobuf::protoc PROPERTIES
-    IMPORTED_LOCATION "${my_protoc}")
+    IMPORTED_LOCATION "${BINARY_DIR}/protoc${CMAKE_EXECUTABLE_SUFFIX}")
+  add_dependencies (protobuf::protoc protobuf_src)
 endif ()
 
 file (MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/proto_gen)
@@ -1230,46 +1301,16 @@ protobuf_generate_cpp (
 set (CMAKE_CURRENT_BINARY_DIR ${save_CBD})
 
 add_library (pbufs STATIC ${PROTO_SRCS} ${PROTO_HDRS})
-if ((NOT TARGET protobuf::libprotobuf) AND (NOT Protobuf_LIBRARIES))
-  message (STATUS "protobuf lib not found - adding unity source for lib")
-  target_sources (pbufs PRIVATE src/ripple/unity/protobuf.cpp)
-  target_include_directories (pbufs
-    PUBLIC
-      src/protobuf/src
-      src/protobuf/vsprojects
-      src/ripple/proto)
-  target_compile_definitions (pbufs
-    PRIVATE
-      _SILENCE_STDEXT_HASH_DEPRECATION_WARNINGS)
-endif ()
+
 target_include_directories (pbufs PRIVATE src)
 target_include_directories (pbufs
-  SYSTEM PUBLIC
-    ${CMAKE_BINARY_DIR}/proto_gen)
-if (NOT MSVC)
-  if (TARGET protobuf::libprotobuf)
-    target_link_libraries (pbufs protobuf::libprotobuf)
-  else ()
-    target_link_libraries (pbufs ${Protobuf_LIBRARIES})
-    target_include_directories (pbufs PUBLIC ${Protobuf_INCLUDE_DIR})
-  endif ()
-endif ()
+  SYSTEM PUBLIC ${CMAKE_BINARY_DIR}/proto_gen)
+target_link_libraries (pbufs protobuf::libprotobuf)
 target_compile_options (pbufs
   PUBLIC
     $<$<BOOL:${is_xcode}>:
       --system-header-prefix="google/protobuf"
       -Wno-deprecated-dynamic-exception-spec
-    >
-    $<$<BOOL:${MSVC}>:
-      -wd4251
-      -wd4146
-    >
-  PRIVATE
-    $<$<BOOL:${MSVC}>:
-      -wd4018
-      -wd4244
-      -wd4800
-      -wd4996
     >)
 add_library (Ripple::pbufs ALIAS pbufs)
 target_link_libraries (ripple_libs INTERFACE Ripple::pbufs)