Configuring Diffie-Hellman Key Exchange Parameters

We recommend using 2048-bit or stronger parameters for Diffie-Hellman key exchange. However, the default key size in OpenSSL is 1024 bits. To configure stronger Diffie-Hellman parameters:

Create a 2048-bit Diffie-Hellman parameter file as follows:
```
$ openssl dhparam -out /etc/ssl/certs/dhparam.pem 2048
```
Modify Nginx configuration file for example with vi editor:
```
$ vi /etc/nginx/sites-available/sshmgr
```
Add the following line with the path to the Diffie-Hellman parameter file to the Nginx configuration file:
```
ssl_dhparam /etc/ssl/certs/dhparam.pem;
```
Restart the Nginx web server services to apply the changes.
```
# service nginx restart
```