Enable SSL/TLS + self signed certificate for http server

Self signed key + cert

• Generagete key + certificate (the validity is 365 days in our example):

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout NAME.key -out NAME.crt

The command will ask for some answers on few questions.

• Copy key/cert to appropriate directory (e.g. /etc/ssl or /etc/apache2/ssl or /etc/nginx/ssl, ...)
• Adjust key's permissions and owner:

chown root: NAME.key
chmod 400 NAME.key

Apache httpd server

• be sure you have installed and enabled apache's SSL/TLS module.
• in appropriate virtual's config add

SSLEngine on
SSLCertificateFile DIRECTORY/NAME.cert
SSLCertificateKeyFile DIRECTORY/NAME.key

• don't forget to restart httpd server

• longer config example

<IfModule mod_ssl.c>
   <VirtualHost _default_:443>
       ServerAdmin webmaster@localhost
       DocumentRoot /var/www/html
       ErrorLog ${APACHE_LOG_DIR}/error.log
       CustomLog ${APACHE_LOG_DIR}/access.log combined
       SSLEngine on
       SSLCertificateFile DIRECTORY/NAME.cert
       SSLCertificateKeyFile DIRECTORY/NAME.key
       <FilesMatch "\.(cgi|shtml|phtml|php)$">
                       SSLOptions +StdEnvVars
       </FilesMatch>
       <Directory /usr/lib/cgi-bin>
                       SSLOptions +StdEnvVars
       </Directory>
   </VirtualHost>
</IfModule>

Nginx httpd server

• be sure you have installed and enabled nginx's SSL/TLS module.

it can be tested with this command (you must see '--with-http_ssl_module' in the output):

~# nginx -V
nginx version: nginx/1.14.2
built with OpenSSL 1.1.1c  28 May 2019 (running with OpenSSL 1.1.1g  21 Apr 2020)
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fdebug-prefix-map=/build/nginx-tBUzFN/nginx-1.14.2=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld- 
opt='-Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock- 
path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp- 
path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with- 
http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_gzip_static_module --without-http_browser_module -- 
without-http_geo_module --without-http_limit_req_module --without-http_limit_conn_module --without-http_memcached_module --without-http_referer_module --without-http_split_clients_module --without- 
http_userid_module --add-dynamic-module=/build/nginx-tBUzFN/nginx-1.14.2/debian/modules/http-echo

• in appropriate server's cfg add

ssl on;
ssl_certificate DIRECTORY/NAME.cert;
ssl_certificate_key DIRECTORY/NAME.key;

• don't forget to restart httpd server

• longer config example

server {
       listen 443;
       access_log  /var/log/nginx/ssl-access.log;
       error_log   /var/log/nginx/ssl-error.log;
       index       index.html;
       root        /usr/share/nginx/html;
       server_name SERVERNAME;
 
       ssl on;
       ssl_certificate DIRECTORY/NAME.cert;
       ssl_certificate_key DIRECTORY/NAME.key;
 
       ssl_session_timeout     5m;
 }