* the certs folder name located in `letsencrypt/live/` must be the `fqdn` of your container responding to the `hostname` command. The full qualified domain name (`fqdn`) inside the docker container is built combining the `hostname` and `domainname` values of the docker-compose file, e. g.: hostname: `mail`; domainname: `myserver.tld`; fqdn: `mail.myserver.tld`
#### Example using docker, nginx-proxy and letsencrypt-nginx-proxy-companion ####
If you are running a web server already, it is non-trivial to generate a Let's Encrypt certificate for your mail server using ```certbot```, because port 80 is already occupied. In the following example, we show how ```docker-mailserver``` can be run alongside the docker containers ```nginx-proxy``` and ```letsencrypt-nginx-proxy-companion```.
There are several ways to start ```nginx-proxy``` and ```letsencrypt-nginx-proxy-companion```. Any method should be suitable here. For example start ```nginx-proxy``` as in the ```letsencrypt-nginx-proxy-companion``` [documentation](https://github.com/JrCs/docker-letsencrypt-nginx-proxy-companion):
Start the rest of your web server containers as usual.
Start another container for your ```mail.myserver.tld```. This will generate a Let's Encrypt certificate for your domain, which can be used by ```docker-mailserver```. It will also run a web server on port 80 at that address.:
```
docker run -d \
--name webmail \
-e "VIRTUAL_HOST=mail.myserver.tld" \
-e "LETSENCRYPT_HOST=mail.myserver.tld" \
-e "LETSENCRYPT_EMAIL=foo@bar.com" \
library/nginx
```
You may want to add ```-e LETSENCRYPT_TEST=true``` to the above while testing to avoid the Let's Encrypt certificate generation rate limits.
The following docker-compose.yml is the basic setup you need for using letsencrypt-nginx-proxy-companion. It is mainly derived from its own wiki/documenation.
The second part of the setup is the actual mail container. So, in another folder, create another docker-compose.yml with the following content (Removed all ENV variables for this example):
The mail container needs to have the letsencrypt certificate folder mounted as a volume. No further changes are needed. The second container is a dummy-sidecar we need, because the mail-container do not expose any web-ports. Set your ENV variables as you need. (VIRTUAL_HOST and LETSENCRYPT_HOST are mandandory, see documentation)
Version 6.2 and later of the Synology NAS DSM OS now come with an interface to generate and renew letencrypt certificates. Navigation into your DSM control panel and go to Security, then click on the tab Certificate to generate and manage letsencrypt certificates. Amongst other things, you can use these to secure your mail server. DSM locates the generated certificates in a folder below ```/usr/syno/etc/certificate/_archive/```. Navigate to that folder and note the 6 character random folder name of the certificate you'd like to use. Then, add the following to your ```docker-compose.yml``` declaration file:
If you are using Caddy to renew your certificates, please note that only RSA certificates work. Read [issue 1440](https://github.com/tomav/docker-mailserver/issues/1440) for details. In short for Caddy v1 the Caddyfile should look something like:
```
https://mail.domain.com {
tls yourcurrentemail@gmail.com {
key_type rsa2048
}
}
```
For Caddy v2 you can specify the key_type in your server's global settings, which would end up looking something like this if you're using a Caddyfile:
```
{
debug
admin localhost:2019
http_port 80
https_port 443
default_sni mywebserver.com
key_type rsa4096
}
````
If you are instead using a json config for Caddy v2, you can set it in your site's TLS automation policies:
[Traefik](https://github.com/containous/traefik) is an open-source Edge Router which handles ACME protocol using [lego](https://github.com/go-acme/lego).
Traefik can request certificates for domains through the ACME protocol (see [Traefik's documentation about its ACME negotiation & storage mechanism](https://docs.traefik.io/https/acme/)). Traefik's router will take care of renewals, challenge negotiations, etc.
Traefik's V2 storage format is natively supported if the `acme.json` store is mounted into the container at `/etc/letsencrypt/acme.json`. The file is also monitored for changes and will trigger a reload of the mail services. Lookup of the certificate domain happens in the following order:
1. $SSL_DOMAIN
2. $HOSTNAME
3. $DOMAINNAME
This allows for support of wild card certificates: `"SSL_DOMAIN=*.example.com"`. Here is an example setup for [docker-compose](https://docs.docker.com/compose/):
This setup only comes with one caveat: The domain has to be configured on another service for traefik to actually request it from lets-encrypt (`whoami` in this case).
##### Traefik V1
If you are using Traefik v1, you might want to _push_ your Traefik-managed certificates to the mailserver container, in order to reuse them. Not an easy task, but fortunately, [youtous/mailserver-traefik](https://github.com/youtous/docker-mailserver-traefik) is a certificate renewal service for docker-mailserver.
Depending of your Traefik configuration, certificates may be stored using a file or a KV Store (consul, etcd...) Either way, certificates will be renewed by Traefik, then automatically pushed to the mailserver thanks to the cert-renewer service. Finally, dovecot and postfix will be restarted.
Note that the certificate will be generate for the container `fqdn`, that is passed as `-h` argument.
Check the following page for more information regarding [postfix and SSL/TLS configuration](http://www.mad-hacking.net/documentation/linux/applications/mail/using-ssl-tls-postfix-courier.xml).
* if a matching certificate (files listed above) is found in `config/ssl`, it will be automatically setup in postfix and dovecot. You just have to place them in `config/ssl` folder.
You can also provide your own certificate files. Add these entries to your `docker-compose.yml`:
volumes:
- /etc/ssl:/tmp/ssl:ro
environment:
- SSL_TYPE=manual
- SSL_CERT_PATH=/tmp/ssl/cert/public.crt
- SSL_KEY_PATH=/tmp/ssl/private/private.key
This will mount the path where your ssl certificates reside as read-only under `/tmp/ssl`. Then all you have to do is to specify the location of your private key and the certificate.
Please note that you may have to restart your mailserver once the certificates change.
ssl=yes and disable_plaintext_auth=no: SSL/TLS is offered to the client, but the client isn't required to use it. The client is allowed to login with plaintext authentication even when SSL/TLS isn't enabled on the connection. This is insecure, because the plaintext password is exposed to the internet.
### Importing certificates obtained via another source
If you have another source for SSL/TLS certificates you can import them into the server via an external script. The external script can be found here: [external certificate import script](https://github.com/hanscees/dockerscripts/blob/master/scripts/tomav-renew-certs)
The steps to follow are these:
1. Transport the new certificates to ./config/sll (/tmp/ssl in the container)
2. You should provide fullchain.key and privkey.pem
3. Place the script in ./config/ (or /tmp/docker-mailserver/ inside the container)
4. Make the script executable (chmod +x tomav-renew-certs.sh )
5. Run the script: docker exec mail /tmp/docker-mailserver/tomav-renew-certs.sh
If an error occurs the script will inform you. If not you will see both postfix and dovecot restart.
After the certificates have been loaded you can check the certificate:
You can ofcourse run the script by cron once a week or something. In that way you could automate cert renewal. If you do so it is probably wise to run an automated check on certificate expiry as well. Such a check could look something like this:
