Import the url with relevant items only

docs/content/tutorials/installation-examples.md

@@ -1,6 +1,143 @@
-It can be useful for new users to see how other projects have built a mailserver from the container `docker-mailserver`.
+## Building a simple mailserver
-Here is a list of such installation pages:
- - https://github.com/docker-scripts/moodle/blob/master/docs/email-setup.md#building-a-simple-mailserver
- - 
 
-(Add other pages that you know)
+We are going to use this docker based mailserver:
+
+- First create a directory for the mailserver and get the setup script:
+  ```
+  mkdir -p /var/ds/mail.example.org
+  cd /var/ds/mail.example.org/
+
+  curl -o setup.sh \
+      https://raw.githubusercontent.com/tomav/docker-mailserver/master/setup.sh
+  chmod a+x ./setup.sh
+  ```
+
+- Create the file `docker-compose.yml` with a content like this:
+  ```
+  version: '2'
+
+  services:
+    mail:
+      image: tvial/docker-mailserver:latest
+      hostname: mail
+      domainname: example.org
+      container_name: mail
+      ports:
+      - "25:25"
+      - "587:587"
+      - "465:465"
+      volumes:
+      - ./data/:/var/mail/
+      - ./state/:/var/mail-state/
+      - ./config/:/tmp/docker-mailserver/
+      - /var/ds/wsproxy/letsencrypt/:/etc/letsencrypt/
+      environment:
+      - PERMIT_DOCKER=network
+      - SSL_TYPE=letsencrypt
+      - ONE_DIR=1
+      - DMS_DEBUG=1
+      - SPOOF_PROTECTION=0
+      - REPORT_RECIPIENT=1
+      - ENABLE_SPAMASSASSIN=0
+      - ENABLE_CLAMAV=0
+      - ENABLE_FAIL2BAN=1
+      - ENABLE_POSTGREY=0
+      cap_add:
+      - NET_ADMIN
+      - SYS_PTRACE
+  ```
+  
+  For more details about the environment variables that can be used,
+  and their meaning and possible values, check also these:
+  - https://github.com/tomav/docker-mailserver#environment-variables
+  - https://github.com/tomav/docker-mailserver/blob/master/.env.dist
+  
+  Make sure to set the propper `domainname` that you will use for the
+  emails. We forward only SMTP ports (not POP3 and IMAP) because we
+  are not interested in accessing the mailserver directly (from a
+  client).  We also use these settings:
+  - `PERMIT_DOCKER=network` because we want to send emails from other
+    docker containers.
+  - `SSL_TYPE=letsencrypt` because we will manage SSL certificates
+    with letsencrypt.
+
+- We need to open these ports on the firewall: `25`, `587`, `465`
+  ```
+  ufw allow 25
+  ufw allow 587
+  ufw allow 465
+  ```
+  On your server you may have to do it differently.
+
+- Pull the docker image:
+  ```
+  docker pull tvial/docker-mailserver:latest
+  ```
+
+- Now generate the DKIM keys with `./setup.sh config dkim` and copy
+  the content of the file `config/opendkim/keys/domain.tld/mail.txt`
+  on the domain zone configuration at the DNS server. I use
+  [bind9](https://github.com/docker-scripts/bind9) for managing my
+  domains, so I just paste it on `example.org.db`:
+  ```
+  mail._domainkey IN      TXT     ( "v=DKIM1; h=sha256; k=rsa; "
+          "p=MIIBIjANBgkqhkiG9w0BAQEFACAQ8AMIIBCgKCAQEAaH5KuPYPSF3Ppkt466BDMAFGOA4mgqn4oPjZ5BbFlYA9l5jU3bgzRj3l6/Q1n5a9lQs5fNZ7A/HtY0aMvs3nGE4oi+LTejt1jblMhV/OfJyRCunQBIGp0s8G9kIUBzyKJpDayk2+KJSJt/lxL9Iiy0DE5hIv62ZPP6AaTdHBAsJosLFeAzuLFHQ6USyQRojefqFQtgYqWQ2JiZQ3"
+          "iqq3bD/BVlwKRp5gH6TEYEmx8EBJUuDxrJhkWRUk2VDl1fqhVBy8A9O7Ah+85nMrlOHIFsTaYo9o6+cDJ6t1i6G1gu+bZD0d3/3bqGLPBQV9LyEL1Rona5V7TJBGg099NQkTz1IwIDAQAB" )  ; ----- DKIM key mail for example.org
+
+  ```
+
+- Add these configurations as well on the same file on the DNS server:
+  ```
+  mail      IN  A   10.11.12.13
+  
+  ; mailservers for example.org
+      3600  IN  MX  1  mail.example.org.
+  
+  ; Add SPF record
+            IN TXT "v=spf1 mx ~all"
+  ```
+  Then don't forget to change the serial number and to restart the service.
+
+- Get an SSL certificate from letsencrypt. I use
+  [wsproxy](https://github.com/docker-scripts/wsproxy) for managing
+  SSL letsencrypt certificates of my domains:
+  ```
+  cd /var/ds/wsproxy
+  ds domains-add mail mail.example.org
+  ds get-ssl-cert myemail@gmail.com mail.example.org --test
+  ds get-ssl-cert myemail@gmail.com mail.example.org
+  ```
+  Now the certificates will be available on
+  `/var/ds/wsproxy/letsencrypt/live/mail.example.org`.
+
+- Start the mailserver and check for any errors:
+  ```
+  apt install docker-compose
+  docker-compose up mail
+  ```
+
+- Create email accounts and aliases:
+  ```
+  ./setup.sh email add admin@example.org passwd123
+  ./setup.sh email add info@example.org passwd123
+  ./setup.sh alias add admin@example.org myemail@gmail.com
+  ./setup.sh alias add info@example.org myemail@gmail.com
+  ./setup.sh email list
+  ./setup.sh alias list
+  ```
+  
+  Aliases make sure that any email that comes to these accounts is
+  forwarded to my real email address, so that I don't need to use
+  POP3/IMAP in order to get these messages. Also no anti-spam and
+  anti-virus software is needed, making the mailserver lighter.
+
+- Send some test emails to these addreses and make other tests. Then
+  stop the container with `Ctrl+c` and start it again as a daemon:
+  `docker-compose up mail -d`.
+
+- Now save on Moodle configuration the SMTP settings and test by
+  trying to send some messages to other users:
+  - **SMTP hosts**: `mail.example.org:465`
+  - **SMTP security**: `SSL`
+  - **SMTP username**: `info@example.org`
+  - **SMTP password**: `passwd123`