(Note: This post is also cross-posted on the Let's Encrypt blog)

As announced earlier this year, Let's Encrypt now issues IP address and six-day certificates to the general public. The Certbot team here at the Electronic Frontier Foundation has been working on two improvements to support these features: the --preferred-profile flag released last year in Certbot 4.0, and the --ip-address flag, new in Certbot 5.3. With these improvements together, you can now use Certbot to get those IP address certificates!

If you want to try getting an IP address certificate using Certbot, install version 5.4 or higher (for webroot support with IP addresses), and run this command:

sudo certbot certonly --staging \
  --preferred-profile shortlived \
  --webroot \
  --webroot-path <filesystem path to webserver root> \
  --ip-address <your ip address>

Two things of note:

• This will request a non-trusted certificate from the Let's Encrypt staging server. Once you've got things working the way you want, run without the --staging flag to get a publicly trusted certificate.
• This requests a certificate with Let's Encrypt's "shortlived" profile, which will be good for 6 days. This is a Let's Encrypt requirement for IP address certificates.

As of right now, Certbot only supports getting IP address certificates, not yet installing them in your web server. There's work to come on that front. In the meantime, edit your webserver configuration to load the newly issued certificate from /etc/letsencrypt/live/<ip address>/fullchain.pem and /etc/letsencrypt/live/<ip address>/privkey.pem.

The command line above uses Certbot's "webroot" mode, which places a challenge response file in a location where your already-running webserver can serve it. This is nice since you don't have to temporarily take down your server.

There are two other plugins that support IP address certificates today: --manual and --standalone. The manual plugin is like webroot, except Certbot pauses while you place the challenge response file manually (or runs a user-provided hook to place the file). The standalone plugin runs a simple web server that serves a challenge response. It has the advantage of being very easy to configure, but has the disadvantage that any running webserver on port 80 has to be temporarily taken down so Certbot can listen on that port. The nginx and apache plugins don't yet support IP addresses.

You should also be sure that Certbot is set up for automatic renewal. Most installation methods for Certbot set up automatic renewal for you. However, since the webserver-specific installers don't yet support IP address certificates, you'll have to set a --deploy-hook that tells your webserver to load the most up-to-date certificates from disk. You can provide this --deploy-hook through the certbot reconfigure command using the rest of the flags above.

We hope you enjoy using IP address certificates with Let's Encrypt and Certbot, and as always if you get stuck you can ask for help in the Let's Encrypt Community Forum.