• support of stronger data ciphers like AES-256-CBC
• new TAP-Driver with a network speed of 1 GBit/s instead of 10 MBit/s
• severe bug on Windows XP SP3 solved where we can't connect to the VPN server

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• OpenSSL_v1.1.1m\ActivePerl-5.20.2.2002-MSWin32-x86-64int-299195.msi
• OpenSSL_v1.1.1m\dmake-4.11.20080107.ppd
• OpenSSL_v1.1.1m\dmake-4.11.20080107.tar.gz
• OpenSSL_v1.1.1m\nasm-2.15.05-installer-x86.exe
• OpenSSL_v1.1.1m\openssl-v1.1.1m.7z

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• LZO_v2.10\lzo-2.10.7z

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• PKCS11-Helper_v1.28.0\pkcs11-helper-1.28.0.7z

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• OpenVPN_v2.5.4\openvpn-2.5.4.7z

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• OpenVPN_v2.5.4\block_dns.c
• OpenVPN_v2.5.4\config-msvc-version.h
• OpenVPN_v2.5.4\openvpn-2.5.4.7z
• OpenVPN_v2.5.4\route.c
• OpenVPN_v2.5.4\tap-windows.h
• OpenVPN_v2.5.4\tap-windows-master_for_XP.7z
• OpenVPN_v2.5.4\tun.c
• OpenVPN_v2.5.4\versionhelpers.h

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• MSYS2\msys2-i686-20160205.exe
• MSYS2\packages_20160205.7z
• OpenVPN-GUI_v11.26\openvpn-gui-11.7z

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• OpenVPN-GUI_v11.26\config.h
• OpenVPN-GUI_v11.26\openvpn-gui-11.7z
• OpenVPN-GUI_v11.26\versionhelpers.h

• Operating System: Windows XP SP3 or Windows Server 2003 R2 SP2
• Compiler Suite: Windows Driver Development Kit v7.1.0 (7600.16385.1)
• NSIS-Installer\nsis-2.50-setup.exe
• TAP-Driver_v9.9.2\tap-windows-master_for_XP.7z

• Operating System: Windows XP SP3 or Windows Server 2003 R2 SP2
• NSIS-Installer\nsis-2.50-setup.exe
• NSIS-Installer\openvpn.nsi
• NSIS-Installer\openvpn-build-release-2.3.7z
• NSIS-Installer\OpenVPN-v2.3.18_last_version_for_XP.exe
• NSIS-Installer\VC-Redistributable_v14.27.29114.0_x86.exe

• TAP-Driver v9.9.2
• NSIS-Installer for OpenVPN v2.5.4

• OpenSSL v1.1.1m
• LZO v2.10 DLL
• PKCS11-Helper v1.28 DLL
• OpenVPN v2.5.4 include files
• OpenVPN v2.5.4
• OpenVPN-GUI v11.26 include files
• OpenVPN-GUI v11.26

• Desktop development with C++
• on the "Installation details" on the right side check:
• MSVC v141 - VS 2017 C++ x64/x86 build tools (v14.16)
• choose tab "Individual components" and select the following on the left side under the category "Compilers, build tools, and runtimes":
• C++ Windows XP Support for VS 2017 (v141) tools [Deprecated]

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• install "OpenSSL_v1.1.1m\ActivePerl-5.20.2.2002-MSWin32-x86-64int-299195.msi" to "C:\Perl"
• install "OpenSSL_v1.1.1m\nasm-2.15.05-installer-x86.exe" to "C:\Program Files (x86)\NASM"
• copy "OpenSSL_v1.1.1m\dmake-4.11.20080107.ppd" to "C:\dmake-4.11.20080107.ppd"
• copy "OpenSSL_v1.1.1m\dmake-4.11.20080107.tar.gz" to "C:\dmake-4.11.20080107.tar.gz"
• unpack "OpenSSL_v1.1.1m\openssl-v1.1.1m.7z" to "C:\openssl-v1.1.1m"
• to build the shared release version open an administrative command prompt and type the following commands:

REM change directory to root of drive C:
cd C:\

REM install DMAKE Perl package
ppm install dmake-4.11.20080107.ppd

REM run VS2019 x86 command line and set correct variables
"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars32.bat"

REM add NASM assembler to path variable
set "PATH=C:\Program Files (x86)\NASM;%PATH%"

REM change current directory to OpenSSL source code directory
cd C:\openssl-v1.1.1m

REM We have to use the configure parameter "-D_WIN32_WINNT=0x0501" for Windows XP and Windows
REM Server 2003.
perl Configure VC-WIN32 -D_WIN32_WINNT=0x0501 --prefix=C:\openssl-v1.1.1m-shared

REM starts the build process and compiles all OpenSSL libraries and files
nmake

REM tests the inner workings of the OpenSSL libraries, this should be run mandatory to be sure
REM that everything works as designed later on
nmake test

REM After this command the installation can be found in the directory "C:\Program Files\OpenSSL".
nmake install

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• unpack "LZO_v2.10\lzo-2.10.7z" to "C:\lzo-2.10"
• to build the DLL release version open an administrative command prompt and type the following commands:

REM run VS2019 x86 command line and set correct variables
"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars32.bat"
  
REM change current directory to LZO source code directory
cd C:\lzo-2.10
  
REM This will build the shared DLLs.
B\win32\vc_dll.bat

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• unpack "PKCS11-Helper_v1.28.0\pkcs11-helper-1.28.0.7z" to "C:\pkcs11-helper-1.28.0"
• to build the DLL release version open an administrative command prompt and type the following commands:

REM run VS2019 x86 command line and set correct variables
"C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Auxiliary\Build\vcvars32.bat"
  
REM change current directory to PKCS11-Helper source code directory
cd C:\pkcs11-helper-1.28.0\lib
  
REM starts the build process and compiles the PKCS11-Helper library
nmake -f Makefile.w32-vc OPENSSL=1 OPENSSL_HOME=C:\openssl-v1.1.1m-shared

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• unpack "OpenVPN_v2.5.4\openvpn-2.5.4.7z" to "C:\openvpn-2.5.4"
• to build the file "config-msvc-version.h" open an administrative command prompt and type the following commands:

REM change current directory to OpenVPN msvc-generate source code directory
cd C:\openvpn-2.5.4\build\msvc\msvc-generate

REM run the java script file with parameters
cscript //Nologo msvc-generate.js --config="C:\openvpn-2.5.4\version.m4" --input="C:\openvpn-2.5.4\config-msvc-version.h.in" --output="C:\openvpn-2.5.4\config-msvc-version.h"

define([PRODUCT_VERSION_PATCH], [.4])

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• unpack "OpenVPN_v2.5.4\openvpn-2.5.4.7z" to "C:\openvpn-2.5.4"
This step is not necessary if you compiled OpenVPN v2.5.4 include files before!
• start Visual Studio 2019 > Create a new project > Empty Project > Next >
Project name: openvpn
Location: C:\Users\Public
Solution name: openvpn
check "Place solution and project in the same directory"
> Create
• copy all files and directories from "C:\openvpn-2.5.4\src\openvpn" to "C:\Users\Public\openvpn"
  Do not overwrite the files "openvpn.vcxproj" and "openvpn.vcxproj.filters".
• delete the following files from the directory "C:\Users\Public\openvpn":
Makefile.am
Makefile.in
• copy the file "C:\openvpn-2.5.4\config-msvc.h" to "C:\Users\Public\openvpn"
• copy the file "C:\openvpn-2.5.4\include\openvpn-msg.h" to "C:\Users\Public\openvpn"
• copy the file "C:\openvpn-2.5.4\include\openvpn-plugin.h" to "C:\Users\Public\openvpn"
• copy the file "OpenVPN_v2.5.4\block_dns.c" to "C:\Users\Public\openvpn" and overwrite the existing file
This newly created C source file contains code to support DNS leak blocking for Windows XP.
• copy the file "OpenVPN_v2.5.4\config-msvc-version.h" to "C:\Users\Public\openvpn"
• copy the file "OpenVPN_v2.5.4\route.c" to "C:\Users\Public\openvpn" and overwrite the existing file
This changes the function get_default_gateway_ipv6 and simply returns, because Windows XP does not support IPv6 at all correctly without a dual stack in combination with IPv4. We can discard this completely and simply return from the function. The implementation of GetBestRoute in Windows XP does not support IPv6 at all.
• copy the file "OpenVPN_v2.5.4\tap-windows.h" to "C:\Users\Public\openvpn"
• copy the file "OpenVPN_v2.5.4\tun.c" to "C:\Users\Public\openvpn" and overwrite the existing file
This changes the function windows_set_mtu to compile on Windows XP. The patch and function will not work at all. We tried several methods to set the MTU without success. Read the comments inside the code for more details.
• copy the file "OpenVPN_v2.5.4\versionhelpers.h" to "C:\Users\Public\openvpn"
• copy "C:\openssl-v1.1.1m-shared" to "C:\Users\Public\openvpn\OpenSSL_v1.1.1m"
• delete the following directories:
C:\Users\Public\openvpn\OpenSSL_v1.1.1m\bin
C:\Users\Public\openvpn\OpenSSL_v1.1.1m\html
• copy "C:\lzo-2.10" to "C:\Users\Public\openvpn\lzo-2.10"
• delete all files and directories in the folder "C:\Users\Public\openvpn\lzo-2.10" except "include", "lzo2.dll" and "lzo2.lib"
• copy "C:\pkcs11-helper-1.28.0" to "C:\Users\Public\openvpn\pkcs11-helper-1.28.0"
• delete all files and directories in the folder "C:\Users\Public\openvpn\pkcs11-helper-1.28.0" except "include" and "lib"
• delete the following files:
C:\Users\Public\openvpn\pkcs11-helper-1.28.0\include\Makefile.am
C:\Users\Public\openvpn\pkcs11-helper-1.28.0\include\Makefile.in
C:\Users\Public\openvpn\pkcs11-helper-1.28.0\include\pkcs11-helper-1.0\Makefile.am
C:\Users\Public\openvpn\pkcs11-helper-1.28.0\include\pkcs11-helper-1.0\Makefile.in
C:\Users\Public\openvpn\pkcs11-helper-1.28.0\include\pkcs11-helper-1.0\pkcs11h-version.h.in
• delete all files in the folder "C:\Users\Public\openvpn\pkcs11-helper-1.28.0\lib" except "libpkcs11-helper-1.dll" and "pkcs11-helper.dll.lib"
• in VS2019 Solution Explorer right click on openvpn "Header Files" > Add > Existing Item... > in the "File name" field enter "*.h" and press Enter > select first header file press Shift and click on the last header file > Add
• right click on openvpn "Resource Files" > Add > Existing Item... > select "openvpn_win32_resources.rc" > Add
• right click on openvpn "Source Files" > Add > Existing Item... > in the "File name" field enter "*.c" and press Enter > select first C source file press Shift and click on the last C source file > Add
• in Solution Explorer right click on "Solution 'openvpn' (1 project)" > Add > New Project... > Empty Project > Next >
Project Name: compat
Location: C:\Users\Public
> Create
• copy all files from "C:\openvpn-2.5.4\src\compat" to "C:\Users\Public\compat"
Do not overwrite the files "openvpn.vcxproj" and "openvpn.vcxproj.filters".
• delete the following files from the directory "C:\Users\Public\compat":
Debug.props
Makefile.am
Makefile.in
PropertySheet.props
Release.props
• copy the file "C:\openvpn-2.5.4\config-msvc.h" to "C:\Users\Public\compat"
• copy the file "OpenVPN_v2.5.4\config-msvc-version.h" to "C:\Users\Public\compat"
• in VS2019 Solution Explorer right click on compat "Header Files" > Add > Existing Item... > in the "File name" field enter "*.h" and press Enter > select first header file press Shift and click on the last header file > Add
• right click on compat "Source Files" > Add > Existing Item... > in the "File name" field enter "*.c" and press Enter > select first C source file press Shift and click on the last C source file > Add
• in Solution Explorer select compat > Menu > Project > Properties > choose Configuration: All Configurations > Platform: All Platforms and change the following values:
Configuration Properties > General
• Platform Toolset: Visual Studio 2017 - Windows XP (v141_xp)
• Configuration Type: Static library (.lib)
Configuration Properties > C/C++ > Preprocessor
• Preprocessor Definitions > choose arrow > <Edit...> > enter
_CRT_SECURE_NO_WARNINGS
> OK
Configuration Properties > C/C++ > Command Line
• Additional Options > enter
/D_WIN32_WINNT=0x0501
Configuration Properties > Linker > Manifest File
• Generate Manifest: No (/MANIFEST:NO)
> OK
• open the file "C:\Users\Public\compat\config-msvc.h" and change code line 1 from

#include <config-msvc-version.h>

to

#include "config-msvc-version.h"

in addition add a new line before line 172 and insert the following code

#define _WIN32_WINNT_VISTA 0x0600

• to solve the warning "Support for targeting Windows XP is deprecated and will not be present in future releases of Visual Studio." do the following steps:
In Solution Explorer select compat > Menu > View > Property Manager > right click "compat" > Add New Project Property Sheet... > Add > expand "compat" > expand "Debug | Win32" > right click on PropertySheet > Properties > Common Properties > User Macros > button "Add Macro":
Name: XPDeprecationWarning
Value: false
> 2 x OK
This property sheets gets added to every build configuration automatically.
• in Solution Explorer select openvpn > Menu > Project > Properties > choose Configuration: All Configurations > Platform: All Platforms and change the following values:
Configuration Properties > General
• Platform Toolset: Visual Studio 2017 - Windows XP (v141_xp)
Configuration Properties > VC++ Directories
• Include Directories > choose arrow > <Edit...> > choose a new line for every value listed here > enter
..\compat
$(SolutionDir)\lzo-2.10\include
$(SolutionDir)\OpenSSL_v1.1.1m\include
$(SolutionDir)\pkcs11-helper-1.28.0\include
> OK
• Library Directories > choose arrow > <Edit...> > choose a new line for every value listed here > enter
$(OutDir)
This is used for compat.lib static library, otherwise the library is not found.
$(SolutionDir)\lzo-2.10
$(SolutionDir)\OpenSSL_v1.1.1m\lib
$(SolutionDir)\pkcs11-helper-1.28.0\lib
> OK
Configuration Properties > C/C++ > General
• Warning Level: Level2 (/W2)
This will suppress 238 warnings. The developers also do this in the original openvpn VS2019 solution.
Configuration Properties > C/C++ > Preprocessor
• Preprocessor Definitions > choose arrow > <Edit...> > enter
_CRT_NONSTDC_NO_DEPRECATE
_CRT_SECURE_NO_WARNINGS
> OK
Configuration Properties > C/C++ > Command Line
• Additional Options > enter
/D_WIN32_WINNT=0x0501
Configuration Properties > Linker > Input
• Additional Dependencies > choose arrow > <Edit...> > enter
compat.lib
libssl.lib
libcrypto.lib
lzo2.lib
pkcs11-helper.dll.lib
gdi32.lib
ws2_32.lib
wininet.lib
crypt32.lib
iphlpapi.lib
winmm.lib
rpcrt4.lib
setupapi.lib
advapi32.lib
> OK
Configuration Properties > Linker > Manifest File
• Generate Manifest: No (/MANIFEST:NO)
> OK
• in Solution Explorer select openvpn > Menu > Project > Project Dependencies... > tab Dependencies > Project: choose openvpn > Depends on: check compat > OK
• open the file "C:\Users\Public\openvpn\config-msvc.h" and change code line 1 from

#include <config-msvc-version.h>

to

#include "config-msvc-version.h"

in addition add a new line before line 172 and insert the following code

#define _WIN32_WINNT_VISTA 0x0600

• open file "C:\Users\Public\openvpn\tun.h" and change the code line 29 from

#include <tap-windows.h>

to

#include "tap-windows.h"

• open file "C:\Users\Public\openvpn\win32.c" and change the code line 50 from

#include <versionhelpers.h>

to

#include "versionhelpers.h"

• open file "C:\Users\Public\openvpn\syshead.h" and change the code line 586 from

#define ENABLE_CRYPTOAPI

to

//#define ENABLE_CRYPTOAPI

• open file "C:\Users\Public\openvpn\console_systemd.c" and change the code line 30 from

#include "config.h"

to

//#include "config.h"

• open file "C:\Users\Public\openvpn\ssl_ncp.h" and change code line 53 from

check_pull_client_ncp(struct context *c, int found);

to

check_pull_client_ncp(struct context *c, const int found);

• open file "C:\Users\Public\openvpn\auth_token.c" and change code line 62 from

const char *state;

to

const char *state = "Invalid";

• open file "C:\Users\Public\openvpn\pkcs11-helper-1.28.0\include\pkcs11-helper-1.0\pkcs11.h" and change code line 1213 from

struct ck_interface **interface,

to

struct ck_interface **Interface,

• to solve the warning "Support for targeting Windows XP is deprecated and will not be present in future releases of Visual Studio." do the following steps:
In Solution Explorer select openvpn > Menu > View > Property Manager > right click "openvpn" > Add New Project Property Sheet... > Add > expand "openvpn" > expand "Debug | Win32" > right click on PropertySheet > Properties > Common Properties > User Macros > button "Add Macro":
Name: XPDeprecationWarning
Value: false
> 2 x OK
This property sheets gets added to every build configuration automatically.
• choose Menu > Build > Configuration Manager... > Active solution configuration: Release > Active solution platform: x86 > Close
• in Solution Explorer select compat > Menu > Project > Properties > choose Configuration: Active(Release) > Platform: Active(Win32) and change the following values:
Configuration Properties > C/C++ > Optimization
• Optimization: Maximum Optimization (Favor Size) (/O1)
• Enable Intrinsic Functions: No
• Favor Size Or Speed: Favor small code (/Os)
> OK
• in Solution Explorer select openvpn > Menu > Project > Properties > choose Configuration: Active(Release) > Platform: Active(Win32) and change the following values:
Configuration Properties > C/C++ > Optimization
• Optimization: Maximum Optimization (Favor Size) (/O1)
• Enable Intrinsic Functions: No
• Favor Size Or Speed: Favor small code (/Os)
Linker > Debugging
• Generate Debug Info: No
> OK
• choose Menu > Build > Rebuild Solution

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• install "MSYS2\msys2-i686-20160205.exe" to "C:\msys32" > uncheck "Run MSYS2 32 bit now." after installation is finished > Finish
Attention: We need at least 2 to 3 GB free space on drive C: to install MSYS2 with all necessary packages!
• unpack "MSYS2\packages_20160205.7z" to "C:\packages_20160205"
• copy all packages from "C:\packages_20160205\all-in-one" directory to "C:\msys32\var\cache\pacman\pkg" directory
• run "C:\msys32\mingw32_shell.bat" as Administrator
• run the following command in MINGW32 shell:

pacman -S autoconf automake libtool make mingw-w64-i686 mingw-w64-i686-toolchain mingw-w64-x86_64 mingw-w64-x86_64-toolchain nasm pkg-config

Press 4 x Enter and 'Y' to install all packages.
This will install all 129 packages which are present inside the pkg directory.
• now we can delete all files in the directory "C:\msys32\var\cache\pacman\pkg"
• unpack "OpenVPN-GUI_v11.26\openvpn-gui-11.7z" to "C:\msys32\home\UserName\openvpn-gui"
• run the following commands in MINGW32 shell:

cd openvpn-gui
autoreconf -i -v
./configure --prefix=/ --host=i686-w64-mingw32 --build=i686-pc-mingw32 --program-prefix='' OPENSSL_CRYPTO_CFLAGS="-I /home/UserName/openssl-v1.1.1m/include/" OPENSSL_CRYPTO_LIBS="-L /home/UserName/openssl-v1.1.1m/lib/ -lcrypto"

• Operating System: Windows 10 x64 Build 21H2
• Compiler Suite: Visual Studio 2019
• unpack "OpenVPN-GUI_v11.26\openvpn-gui-11.7z" to "C:\openvpn-gui"
• start Visual Studio 2019 > Create a new project > Empty Project > Next >
Project name: openvpn-gui
Location: C:\Users\Public
Solution name: openvpn-gui
check "Place solution and project in the same directory"
> Create
• copy all files and directories from "C:\openvpn-gui" to "C:\Users\Public\openvpn-gui"
• delete the following files from the directory "C:\Users\Public\openvpn-gui":
aclocal.m4
compile
config.guess
config.h.in
config.sub
configure
configure.ac
COPYING
COPYRIGHT.GPL
depcomp
install-sh
Makefile.am
Makefile.in
missing
• move all files from the directory "C:\Users\Public\openvpn-gui\res" to "C:\Users\Public\openvpn-gui"
• delete the directory "C:\Users\Public\openvpn-gui\res"
• copy the file "OpenVPN-GUI_v11.26\config.h" to "C:\Users\Public\openvpn-gui"
• copy the file "OpenVPN-GUI_v11.26\versionhelpers.h" to "C:\Users\Public\openvpn-gui"
• delete the directory "C:\OpenSSL_v1.1.1m" if it is present
• unpack "OpenSSL_v1.1.1m\openssl-v1.1.1m-shared.7z" to "C:\OpenSSL_v1.1.1m"
• copy "C:\OpenSSL_v1.1.1m" to "C:\Users\Public\openvpn-gui\OpenSSL_v1.1.1m"
• delete the following directories:
C:\Users\Public\openvpn-gui\OpenSSL_v1.1.1m\bin
C:\Users\Public\openvpn-gui\OpenSSL_v1.1.1m\html
• in VS2019 Solution Explorer right click on openvpn-gui "Header Files" > Add > Existing Item... > in the "File name" field enter "*.h" and press Enter > select first header file press Shift and click on the last header file > Add
• right click on "Resource Files" > Add > Existing Item... > select "openvpn-gui-res.rc" > Add
• right click on "Source Files" > Add > Existing Item... > in the "File name" field enter "*.c" and press Enter > select first C source file press Shift and click on the last C source file > Add
• in Solution Explorer select openvpn-gui > Menu > Project > Properties > choose Configuration: All Configurations > Platform: All Platforms and change the following values:
Configuration Properties > General
• Platform Toolset: Visual Studio 2017 - Windows XP (v141_xp)
• Character Set: Use Unicode Character Set
Configuration Properties > VC++ Directories
• Include Directories > choose arrow > <Edit...> > choose New Line > enter
$(SolutionDir)\OpenSSL_v1.1.1m\include
> OK
• Library Directories > choose arrow > <Edit...> > choose New Line > enter
$(SolutionDir)\OpenSSL_v1.1.1m\lib
> OK
Configuration Properties > C/C++ > Preprocessor
• Preprocessor Definitions > choose arrow > <Edit...> > enter
_CRT_NONSTDC_NO_DEPRECATE
_CRT_SECURE_NO_WARNINGS
> OK
Configuration Properties > C/C++ > Command Line
• Additional Options > enter
/D "HAVE_CONFIG_H" /D "WIN32_LEAN_AND_MEAN" /D_WIN32_WINNT=0x0501
Configuration Properties > Linker > Input
• Additional Dependencies > choose arrow > <Edit...> > enter
ws2_32.lib
libcrypto.lib
libssl.lib
secur32.lib
netapi32.lib
comctl32.lib
wininet.lib
wtsapi32.lib
crypt32.lib
shlwapi.lib
winhttp.lib
> OK
Configuration Properties > Linker > Manifest File
• Generate Manifest: No (/MANIFEST:NO)
Configuration Properties > Linker > System
• SubSystem: Windows (/SUBSYSTEM:WINDOWS)
Configuration Properties > Resources > Command Line
• Additional Options > enter
/D "HAVE_CONFIG_H"

> OK
• Menu > Build > Rebuild Solution > Menu > View > Error List
• click on all errors "Cannot open include file: 'config.h': No such file or directory" and change the line from

#include <config.h>

to

#include "config.h"

• click on all errors "'wcstok': too few arguments for call" and change the first code location from

pch = wcstok(buf, L"\r\n");

to

wchar_t *state;
pch = wcstok(buf, L"\r\n", &state);

change the second code location from

pch = wcstok(NULL, L"\r\n");

to

pch = wcstok(NULL, L"\r\n", &state);

• Menu > Build > Rebuild Solution > Menu > View > Error List
• click on all errors "'wcstok': too few arguments for call" and change the first code location from

LPWSTR token = wcstok(proxy_str, delim);

to

wchar_t *state;
LPWSTR token = wcstok(proxy_str, delim, &state);

change the second code location from

token = wcstok(NULL, delim);

to

token = wcstok(NULL, delim, &state);

• click on error "'AURL_ENABLEURL': undeclared identifier" and change the code from

SendMessage(hmsg, EM_AUTOURLDETECT, AURL_ENABLEURL, 0);

to

#define AURL_ENABLEURL 1
SendMessage(hmsg, EM_AUTOURLDETECT, AURL_ENABLEURL, 0);

• click on both errors "Cannot open include file 'versionhelpers.h': No such file or directory" and change the code location from

#include <versionhelpers.h>

to

#include "versionhelpers.h"

• click on error "Cannot open include file 'combaseapi.h': No such file or directory" and change the code location from

#include <combaseapi.h>

to

//#include <combaseapi.h>

• Menu > Build > Rebuild Solution > Menu > View > Error List
• click on warning "formal parameter 2 different from declaration" right click on the function IsUserInGroup > Go To Declaration > change code location from

static BOOL IsUserInGroup(PSID sid, PTOKEN_GROUPS token_groups, const WCHAR *group_name);

to

static BOOL IsUserInGroup(PSID sid, const PTOKEN_GROUPS token_groups, const WCHAR *group_name);

• click on warning "'CompareStringOrdinal' undefined; assuming extern returning int" and change the code location from

int cmp = CompareStringOrdinal(nameval1, (int)len1, nameval2, (int)len2, ignore_case);

to

//int cmp = CompareStringOrdinal(nameval1, (int)len1, nameval2, (int)len2, ignore_case);
int cmp = wcsncmp(nameval1, nameval2, (len1 > len2 ? len2 : len1));

• click on warning "'=': conversion from 'DWORD' to 'LANGID', possible loss of data" and change code location from

gui_language = ( value != 0 ? value : GetUserDefaultUILanguage() );

to

gui_language = (LANGID)( value != 0 ? value : GetUserDefaultUILanguage() );

• click on warning "formal parameter 2 different from declaration" and change code location from

LoadLocalizedStringBuf(PTSTR buffer, int bufferSize, const UINT stringId, ...)

to

LoadLocalizedStringBuf(PTSTR buffer, const int bufferSize, const UINT stringId, ...)

• click on warning "'function': conversion from 'DWORD' to 'u_short', possible loss of data and change code location from

c->manage.skaddr.sin_port = htons(o.mgmt_port_offset + config);

to

c->manage.skaddr.sin_port = htons((u_short)o.mgmt_port_offset + config);

• click on warning "'RegGetValueW' undefined; assuming extern returning int" and change code location from

if (RegGetValueW (regkey, NULL, L"version", RRF_RT_REG_BINARY, NULL, v, &len)

to

//if (RegGetValueW (regkey, NULL, L"version", RRF_RT_REG_BINARY, NULL, v, &len)
if (RegQueryValueEx(regkey, L"version", NULL, NULL, (LPBYTE)v, &len)

• click on warning "'RegCopyTree' undefined; assuming extern returning int" and change code location from

status = RegCopyTree (regkey_nilings, NULL, regkey_proxy);

to

//status = RegCopyTree (regkey_nilings, NULL, regkey_proxy);
status = SHCopyKey(regkey_nilings, NULL, regkey_proxy, 0);

• click on warning "'RegDeleteTree' undefined; assuming extern returning int" and change code location from

RegDeleteTree (HKEY_CURRENT_USER, GUI_REGKEY_HKCU); /* delete all values and subkeys */

to

//RegDeleteTree (HKEY_CURRENT_USER, GUI_REGKEY_HKCU); /* delete all values and subkeys */
SHDeleteKey(HKEY_CURRENT_USER, GUI_REGKEY_HKCU); /* delete all values and subkeys */

• go to the start of the C source file registry.c and place the following include after <shlobj.h>

#include <shlwapi.h>

• Menu > Build > Rebuild Solution > Menu > View > Error List
• click on error "'TTI_ERROR_LARGE': undeclared identifier" and change the code location from

bt.ttiIcon = TTI_ERROR_LARGE;

to

#define TTI_ERROR_LARGE 6
bt.ttiIcon = TTI_ERROR_LARGE;

• click on error "'IID_IFileOpenDialog': undeclared identifier", comment out the complete function "BrowseFolder" and add the following replacement functions

INT CALLBACK BrowseCallbackProc(HWND hwnd, UINT uMsg, LPARAM lp, LPARAM pData)
{
    if (uMsg == BFFM_INITIALIZED) SendMessage(hwnd, BFFM_SETSELECTION, TRUE, pData);
    return 0;
}

static BOOL BrowseFolder(const WCHAR * initial_path, WCHAR * selected_path, size_t selected_path_size)
{
    HRESULT initResult = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED);
    if (FAILED(initResult))
    {
        return false;
    }

    BROWSEINFO br;
    ZeroMemory(&br, sizeof(BROWSEINFO));
    br.lpfn = BrowseCallbackProc;
    br.ulFlags = BIF_RETURNONLYFSDIRS | BIF_NEWDIALOGSTYLE;
    br.hwndOwner = NULL;
    br.lParam = (LPARAM)initial_path;

    LPITEMIDLIST pidl = NULL;
    if ((pidl = SHBrowseForFolder(&br)) != NULL)
    {
        wchar_t path[MAX_PATH];
        if (SHGetPathFromIDList(pidl, path))
        {
            wcsncpy(selected_path, path, wcslen(path));
        }
    }

    CoUninitialize();

    return true;
}

• Menu > Build > Rebuild Solution > Menu > View > Error List
• click on error "cannot open include file '../openvpn-gui-res.h'." and change the code location from

#include "../openvpn-gui-res.h"

to

#include "openvpn-gui-res.h"

• click on warning "'function': conversion from 'time_t' to 'unsigned int', possible loss of data" and change the code location from

srand(time(NULL));

to

srand((unsigned int)time(NULL));

• click on warning "'initializing': conversion from 'unsigned __int64' to 'double', possible loss of data" and change the code location from

double x = c;

to

double x = (double)c;

• click on warning "'function': conversion from 'time_t' to 'unsigned int', possible loss of data" and change the code location from

srand(time(NULL));

to

srand((unsigned int)time(NULL));

• click on warning "'function': different 'const' qualifiers" and change the code location from

void *tmp = realloc(options->auto_connect, sizeof(wchar_t *)*options->max_auto_connect);

to

void *tmp = realloc((void*)options->auto_connect, sizeof(wchar_t *)*options->max_auto_connect);

• to solve the warning "Support for targeting Windows XP is deprecated and will not be present in future releases of Visual Studio." do the following steps:
Menu > View > Property Manager > right click "openvpn-gui" > Add New Project Property Sheet... > Add > expand "openvpn-gui" > expand "Debug | Win32" > right click on PropertySheet > Properties > Common Properties > User Macros > button "Add Macro":
Name: XPDeprecationWarning
Value: false
> 2 x OK
This property sheets gets added to every build configuration automatically.
• choose Menu > Build > Configuration Manager... > Active solution configuration: Release > Active solution platform: x86 > Close
• in Solution Explorer select openvpn-gui > Menu > Project > Properties > choose Configuration: Active(Release) > Platform: Active(Win32) and change the following values:
Configuration Properties > C/C++ > Optimization
• Optimization: Maximum Optimization (Favor Size) (/O1)
• Enable Intrinsic Functions: No
• Favor Size Or Speed: Favor small code (/Os)
Linker > Debugging
• Generate Debug Info: No
> OK
• choose Menu > Build > Rebuild Solution

• Operating System: Windows XP SP3 or Windows Server 2003 R2 SP2
• Compiler Suite: Windows Driver Development Kit v7.1.0 (7600.16385.1)
• install "NSIS-Installer\nsis-2.50-setup.exe"
• unpack "TAP-Driver_v9.9.2\tap-windows-master_for_XP.7z" to "C:\tap"
• open file "C:\tap\src\tapdrvr.c" and change code line 1142 from

l_Query.m_Long = 100000; // rate / 100 bps

to

l_Query.m_Long = 10000000; // rate / 100 bps

• to build the release driver open an administrative command prompt and type the following commands:

REM change current directory to TAP-Driver source code directory
cd "C:\tap"

REM configure TAP-Driver
configure.bat

REM build TAP-Driver
build.bat

• the resulting NSIS-Installer package is located at "C:\tap\tap-windows-9.9.2.exe"

• Operating System: Windows XP SP3 or Windows Server 2003 R2 SP2
• install "NSIS-Installer\nsis-2.50-setup.exe"
• create the directory "C:\nsis"
• unpack "NSIS-Installer\OpenVPN-v2.3.18_last_version_for_XP.exe" to "C:\nsis\OpenVPN-v2.3.18"
• unpack "NSIS-Installer\openvpn-build-release-2.3.7z" to "C:\nsis\openvpn-build-release-2.3"
• copy "C:\nsis\openvpn-build-release-2.3\windows-nsis\install-whirl.bmp" to "C:\nsis"
• copy "C:\nsis\openvpn-build-release-2.3\windows-nsis\nsProcess.dll" to "C:\nsis"
• copy "C:\nsis\openvpn-build-release-2.3\windows-nsis\nsProcess.nsh" to "C:\nsis"
• copy "NSIS-Installer\VC-Redistributable_v14.27.29114.0_x86.exe" to "C:\nsis"
• delete the directory "C:\nsis\OpenVPN-v2.3.18\$PLUGINSDIR"
• delete the file "C:\nsis\OpenVPN-v2.3.18\$TEMP\tap-windows.exe"
• delete all files and directories in the folder "C:\nsis\OpenVPN-v2.3.18\bin" except "openvpnserv.exe"
• unpack "OpenSSL_v1.1.1m\openssl-v1.1.1m-shared.7z" to "C:\OpenSSL_v1.1.1m"
• copy "C:\OpenSSL_v1.1.1m\bin\libcrypto-1_1.dll" to "C:\nsis\OpenVPN-v2.3.18\bin"
• copy "C:\OpenSSL_v1.1.1m\bin\libssl-1_1.dll" to "C:\nsis\OpenVPN-v2.3.18\bin"
• copy "C:\OpenSSL_v1.1.1m\bin\openssl.exe" to "C:\nsis\OpenVPN-v2.3.18\bin"
• unpack "PKCS11-Helper_v1.28.0\pkcs11-helper-1.28.0-shared-DLL.7z" to "C:\pkcs11-helper-1.28.0"
• copy "C:\pkcs11-helper-1.28.0\lib\libpkcs11-helper-1.dll" to "C:\nsis\OpenVPN-v2.3.18\bin"
• unpack "LZO_v2.10\lzo-2.10-shared-DLL.7z" to "C:\lzo-2.10"
• copy "C:\lzo-2.10\lzo2.dll" to "C:\nsis\OpenVPN-v2.3.18\bin"
• unpack "OpenVPN_v2.5.4\openvpn_v2.5.4_20220123_for_XP.7z" to "C:\openvpn_v2.5.4_20220123_for_XP"
• copy "C:\openvpn_v2.5.4_20220123_for_XP\bin\openvpn.exe" to "C:\nsis\OpenVPN-v2.3.18\bin"
• unpack "OpenVPN-GUI_v11.26\openvpn-gui_v11.26_20220123_for_XP.7z" to "C:\openvpn-gui_v11.26_20220123_for_XP"
• copy "C:\openvpn-gui_v11.26_20220123_for_XP\bin\openvpn-gui.exe" to "C:\nsis\OpenVPN-v2.3.18\bin"
• copy "C:\tap\tap-windows-9.9.2.exe" to "C:\nsis\OpenVPN-v2.3.18\$TEMP\tap-windows.exe"
• delete the directory "C:\nsis\openvpn-build-release-2.3"
• copy "NSIS-Installer\openvpn.nsi" to "C:\nsis\openvpn.nsi"
• Start > Programs > NSIS > Compile NSI scripts
• Menu > File > Load Script... > choose file "C:\nsis\openvpn.nsi" > Open > the NSI script is compiled automatically we should not see any errors at the end of compilation > Close > close NSIS compiler window

• block-outside-dns
• route-ipv6 ::/0
• auth-nocache

ERROR: Windows route add ipv6 command failed: returned error code 1

WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this

block-outside-dns
#route-ipv6 ::/0
auth-nocache

• https://hide.me/en/check
Checks the IP address and the provider that uses this address. This should display only servers of your VPN network.




• https://www.dnsleaktest.com
Checks for DNS leaks. DNS leaks can show the internet browsing history if the traffic is not routed correctly.




• https://ipleak.net
Checks for DNS leaks and WebRTC leaks.

• Mozilla Firefox: Type "about:config" in the address bar, scroll down to "media.peerconnection.enabled", double click to set it to false
• Google Chrome: Install Google official extension WebRTC Network Limiter
• Opera: Type "about:config" in the address bar or go to "Settings", select "Show advanced settings" and click on "Privacy & security". At "WebRTC" mark select "Disable non-proxied UDP".

2022-01-09 14:24:02 open_tun
2022-01-09 14:24:02 MANAGEMENT: Client disconnected
2022-01-09 14:24:02 fatal buffer size error, size=2089877947
2022-01-09 14:24:02 Exiting due to fatal error

ULONG dev_interface_list_size;

ULONG dev_interface_list_size = 0;