131 lines
4.9 KiB
Markdown
131 lines
4.9 KiB
Markdown
---
|
|
title: Obtain a Certificate
|
|
date: 2019-03-03T16:39:46+01:00
|
|
draft: false
|
|
weight: 2
|
|
---
|
|
|
|
This guide explains various ways to obtain a new certificate.
|
|
|
|
<!--more-->
|
|
|
|
## Using the built-in web server
|
|
|
|
Open a terminal, and execute the following command (insert your own email address and domain):
|
|
|
|
```bash
|
|
lego --email="you@example.com" --domains="example.com" --http run
|
|
```
|
|
|
|
You will find your certificate in the `.lego` folder of the current working directory:
|
|
|
|
```console
|
|
$ ls -1 ./.lego/certificates
|
|
example.com.crt
|
|
example.com.issuer.crt
|
|
example.com.json
|
|
example.com.key
|
|
[maybe more files for different domains...]
|
|
```
|
|
|
|
where
|
|
|
|
- `example.com.crt` is the server certificate (including the CA certificate),
|
|
- `example.com.key` is the private key needed for the server certificate,
|
|
- `example.com.issuer.crt` is the CA certificate, and
|
|
- `example.com.json` contains some JSON encoded meta information.
|
|
|
|
For each domain, you will have a set of these four files.
|
|
For wildcard certificates (`*.example.com`), the filenames will look like `_.example.com.crt`.
|
|
|
|
The `.crt` and `.key` files are PEM-encoded x509 certificates and private keys.
|
|
If you're looking for a `cert.pem` and `privkey.pem`, you can just use `example.com.crt` and `example.com.key`.
|
|
|
|
|
|
## Using a DNS provider
|
|
|
|
If you can't or don't want to start a web server, you need to use a DNS provider.
|
|
lego comes with [support for many]({{% ref "dns#dns-providers" %}}) providers,
|
|
and you need to pick the one where your domain's DNS settings are set up.
|
|
Typically, this is the registrar where you bought the domain, but in some cases this can be another third-party provider.
|
|
|
|
For this example, let's assume you have set up CloudFlare for your domain.
|
|
|
|
Execute this command:
|
|
|
|
```bash
|
|
CLOUDFLARE_EMAIL="you@example.com" \
|
|
CLOUDFLARE_API_KEY="yourprivatecloudflareapikey" \
|
|
lego --email "you@example.com" --dns cloudflare --domains "example.org" run
|
|
```
|
|
|
|
|
|
## Using a custom certificate signing request (CSR)
|
|
|
|
The first step in the process of obtaining certificates involves creating a signing request.
|
|
This CSR bundles various information, including the domain name(s) and a public key.
|
|
By default, lego will hide this step from you, but if you already have a CSR, you can easily reuse it:
|
|
|
|
```bash
|
|
lego --email="you@example.com" --http --csr="/path/to/csr.pem" run
|
|
```
|
|
|
|
lego will infer the domains to be validated based on the contents of the CSR, so make sure the CSR's Common Name and optional SubjectAltNames are set correctly.
|
|
|
|
|
|
## Using an existing, running web server
|
|
|
|
If you have an existing server running on port 80, the `--http` option also requires the `--http.webroot` option.
|
|
This just writes the http-01 challenge token to the given directory in the folder `.well-known/acme-challenge` and does not start a server.
|
|
|
|
The given directory **should** be publicly served as `/` on the domain(s) for the validation to complete.
|
|
|
|
If the given directory is not publicly served you will have to support rewriting the request to the directory;
|
|
|
|
You could also implement a rewrite to rewrite `.well-known/acme-challenge` to the given directory `.well-known/acme-challenge`.
|
|
|
|
You should be able to run an existing webserver on port 80 and have lego write the token file with the HTTP-01 challenge key authorization to `<webroot dir>/.well-known/acme-challenge/` by running something like:
|
|
|
|
```bash
|
|
lego --accept-tos --email you@example.com --http --http.webroot /path/to/webroot --domains example.com run
|
|
```
|
|
|
|
## Running a script afterward
|
|
|
|
You can easily hook into the certificate-obtaining process by providing the path to a script:
|
|
|
|
```bash
|
|
lego --email="you@example.com" --domains="example.com" --http run --run-hook="./myscript.sh"
|
|
```
|
|
|
|
Some information is provided through environment variables:
|
|
|
|
- `LEGO_ACCOUNT_EMAIL`: the email of the account.
|
|
- `LEGO_CERT_DOMAIN`: the main domain of the certificate.
|
|
- `LEGO_CERT_PATH`: the path of the certificate.
|
|
- `LEGO_CERT_KEY_PATH`: the path of the certificate key.
|
|
- `LEGO_CERT_PEM_PATH`: (only with `--pem`) the path to the PEM certificate.
|
|
- `LEGO_CERT_PFX_PATH`: (only with `--pfx`) the path to the PFX certificate.
|
|
|
|
### Use case
|
|
|
|
A typical use case is distribute the certificate for other services and reload them if necessary.
|
|
Since PEM-formatted TLS certificates are understood by many programs, it is relatively simple to use certificates for more than a web server.
|
|
|
|
This example script installs the new certificate for a mail server, and reloads it.
|
|
Beware: this is just a starting point, error checking is omitted for brevity.
|
|
|
|
```bash
|
|
#!/bin/bash
|
|
|
|
# copy certificates to a directory controlled by Postfix
|
|
postfix_cert_dir="/etc/postfix/certificates"
|
|
|
|
# our Postfix server only handles mail for @example.com domain
|
|
if [ "$LEGO_CERT_DOMAIN" = "example.com" ]; then
|
|
install -u postfix -g postfix -m 0644 "$LEGO_CERT_PATH" "$postfix_cert_dir"
|
|
install -u postfix -g postfix -m 0640 "$LEGO_CERT_KEY_PATH" "$postfix_cert_dir"
|
|
|
|
systemctl reload postfix@-service
|
|
fi
|
|
```
|