Installing SSL Certificates

To keep your communications secure, Zulip runs over HTTPS only. You’ll need an SSL/TLS certificate.

Fortunately, since about 2017, new options can make getting and maintaining a genuine, trusted-by-browsers certificate no longer the chore (nor expense) that it used to be.

Manual install

If you already have an SSL certificate, just install (or symlink) its files into place at the following paths:

  • /etc/ssl/private/zulip.key for the private key
  • /etc/ssl/certs/zulip.combined-chain.crt for the certificate.

Your certificate file should contain not only your own certificate but its full chain, including any intermediate certificates used by your CA. See the nginx documentation for details on what this means and how to do it and test it. If you’re missing part of the chain, your server may work with some browsers but not others.

Self-signed certificate

If you aren’t able to use Certbot, you can generate a self-signed SSL certificate. This isn’t suitable for production use (because it’s insecure, and because browsers and the Zulip apps will complain that it’s insecure), but may be convenient for testing.

To generate a self-signed certificate when first installing Zulip, just pass the --self-signed-cert flag when running the install script.

To generate a self-signed certificate for an already-installed Zulip server, run the following commands:

sudo -s  # If not already root
/home/zulip/deployments/current/scripts/setup/generate-self-signed-cert HOSTNAME

where HOSTNAME is the domain name (or IP address) to use on the generated certificate.