Create selfsigned OpenVPN certificate

#!/bin/sh
openssl req -x509 -sha256 -days 1825 -newkey rsa:2048 -keyout rootCA.key -out rootCA.crt
cat <<EOF > domain.ext
authorityKeyIdentifier=keyid,issuer
basicConstraints=CA:FALSE
subjectAltName = @alt_names
[alt_names]
DNS.1 = lg416.synology.me
EOF
openssl req -newkey rsa:4096 -nodes -keyout domain.key -out domain.csr
openssl x509 -req -CA rootCA.crt -CAkey rootCA.key -in domain.csr -out domain.crt -days 3650 -CAcreateserial -extfile domain.ext