Idea for improving the FAQ

[thomasb9511]

Continuing the discussion from Frequently Asked Questions (FAQ):

@josh

Can I use an existing private key or Certificate Signing Request (CSR) with the Let's Encrypt client?

Yes, you can obtain a certificate for an existing private key (if the key is an appropriate type and size), and, if you want, you can use an existing CSR.

How would one do this. It would be nice to have a little something that showed how to do it.