Issue

When configure openvpn with the command below.

./configure --prefix=/opt/openvpn-2.4.9

But the following error occurs.

checking for setcon in -lselinux... no
checking for pam_start in -lpam... no
checking for PKCS11_HELPER... no
checking for OPENSSL... no
checking for SSL_CTX_new... no
configure: error: openssl check failed

Solution

We should install openssl.

1. Install from source

Download the source and config.

$ wget https://www.openssl.org/source/openssl-1.1.1g.tar.gz
$ tar xf openssl-1.1.1g.tar.gz
$ cd openssl-1.1.1g
$ ./config
$ make
$ make test
$ make install

2. Install with command

Ubuntu/Debian

• On the https://pkgs.org/search/?q=libssl webpage, find the libssl-dev packages that match your operating system, download and install.
• Use the apt-get command.

sudo apt-get install libssl-dev

RHEL/CentOS

• On the https://pkgs.org/search/?q=openssl-devel webpage, find the openssl-devel packages that match your operating system, download and install.
• Use the yum command.

sudo yum install openssl-devel