SoftEther 在 Linux 下需要手动编译安装。不管是 官网 还是 Github，
下载的源码都无法成功编译，提示以下错误，

  1. 官网 (softether-vpnclient-v4.22-9634-beta-2016.11.27-linux-x64-64bit.tar.gz)

     ...(略)
 ranlib code/vpnclient.a
 gcc code/vpnclient.a -O2 -fsigned-char -pthread -m64 -lm -ldl -lrt -lpthread -L./ lib/libssl.a lib/libcrypto.a lib/libiconv.a lib/libcharset.a lib/libedit.a lib/libncurses.a lib/libz.a lib/libintelaes.a -o vpnclient
 /usr/bin/ld: code/vpnclient.a(vpnclient.o): relocation R_X86_64_32 against symbol `StopProcess' can not be used when making a shared object; recompile with -fPIC
 /usr/bin/ld: code/vpnclient.a(Unix.o): relocation R_X86_64_32 against `.data' can not be used when making a shared object; recompile with -fPIC
 ...(略)
 collect2: error: ld returned 1 exit status
 Makefile:18: recipe for target 'i_read_and_agree_the_license_agreement' failed
 make[1]: *** [i_read_and_agree_the_license_agreement] Error 1
 make[1]: Leaving directory '/opt/vpnclient'
 ...(略)

  2. github (#e9006fa)

    % make
cc -DNDEBUG -DVPN_SPEED -DUNIX -DUNIX_LINUX -DCPU_64 -D_REENTRANT -DREENTRANT -D_THREAD_SAFE -D_THREADSAFE -DTHREAD_SAFE -DTHREADSAFE -D_FILE_OFFSET_BITS=64 -I./src/ -I./src/Cedar/ -I./src/Mayaqua/ -O2 -fsigned-char -m64 -c src/Mayaqua/Encrypt.c -o tmp/objs/Mayaqua/Encrypt.o
src/Mayaqua/Encrypt.c: In function ‘Enc_tls1_P_hash’:
src/Mayaqua/Encrypt.c:175:11: error: storage size of ‘ctx’ isn’t known
  HMAC_CTX ctx;
...(略)

最后在 论坛 找到回避方法，

ha found a woraround
instead of installing libssl-dev you have to install libssl1.0-dev
this way you also install openssl v1.0.x on your debian 9 system.

it also requires this patch to disable sslv3 support

  1. 安装 libssl1.0-dev 替代 libssl-dev

  2. 修改代码禁用 sslv3

     src/Mayaqua/Network.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git src/Mayaqua/Network.c src/Mayaqua/Network.c
index 41d69cc..77a4773 100644
--- src/Mayaqua/Network.c
+++ src/Mayaqua/Network.c
@@ -13013,7 +13013,7 @@ bool StartSSLEx(SOCK *sock, X *x, K *priv, bool client_tls, UINT ssl_timeout, ch
				}
				else
				{
-                       if (client_tls == false)
+                       if (true == false)
						{
								SSL_CTX_set_ssl_version(ssl_ctx, SSLv3_method());
						}