Ansible-mailserver

Ansible configured Postfix & dovecot server

A fullstack but simple mail server (smtp, imap, antispam). Only configuration files, no SQL database. Keep it simple and versioned. Easy to deploy and upgrade. (Inspired by cd)

Setup server

On an ubuntu lts server:

apt update
apt install -y git ansible
git clone https://github.com/chrisjsimpson/ansible-mailserver.git
cd ansible-mailserver/

How to run

Configure ansible inventory file with your host (e.g. ip of a vps instance https://www.vultr.com/?ref=8472727)

If you're running ansible directly on the server:

[mailservers]
localhost ansible_user=root ansible_connection=local

Otherwise:

[mailservers]
<your mailserver ip> ansible_user=root

Configure DNS (so that cert generation passes)

• A record for email.example.co.uk
• MX record pointing to A record

Run Playboks

• Certs (uses certbot to get a certificate)
• Mail server configuration

Run the cert playbook to generate a cert for the server:

ansible-playbook -i playbooks/inventory.yaml -e [email protected] -e domain=email.example.com playbooks/certs/certs.yaml

Where

• -i is the inventory.yaml file
• -e [email protected] the email address used for certbot terms of service
• -e domain=email.example.com the domain of the email server you want a certificate for
• playbooks/certs.yaml contains the automated steps to get a certificate (aka a playbook)

Success looks like:

PLAY RECAP ************************************************************************************************************************
localhost                  : ok=3    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0  

Run the mail server playbook:

This will configure your server with postfix, dovecot, opendkim and spamassassin.

ansible-playbook -i playbooks/inventory.yaml -e myhostname=email.example.com -e [email protected] -e generate_dkim_keys=True playbooks/mailserver/mail-server.yaml

DKIM will fail:

TASK [Make opendkim the owner of dkim all keys] ***********************************************************************************
failed: [localhost] (item=example.co.uk) => {"ansible_loop_var": "item", "changed": false, "item": "example.co.uk", "msg": "file (/etc/opendkim/keys/example.co.uk/default.private) is absent, cannot continue", "path": "/etc/opendkim/keys/example.co.uk/default.private"}

PLAY RECAP ************************************************************************************************************************
localhost                  : ok=23   changed=22   unreachable=0    failed=1    skipped=1    rescued=0    ignored=0 

(re)Generate DKIM keys for a single domain

Update playbooks/group_vars/mailservers.yaml, setting virtual_mailbox_domains and regenerate_dkim_keys_domains. Then ansible will only generate new keys for the domain in regenerate_dkim_keys_domains.

e.g:

virtual_mailbox_domains: ['example.com']
regenerate_dkim_keys_domains: ['example.com']

Then run the playboook:

ansible-playbook -i playbooks/inventory.yaml playbooks/dkim/dkim-keys-generation.yaml

Run the cert renewal for crontab entry

ansible-playbook -i playbooks/inventory.yaml -e [email protected] -e domain=email.example.com playbooks/certs/cron-cert.yaml

Re-run mail-server playbook

ansible-playbook -i playbooks/inventory.yaml -e myhostname=email.example.com -e [email protected] -e generate_dkim_keys=True playbooks/mailserver/mail-server.yaml

Success looks like:

PLAY RECAP ************************************************************************************************************************
localhost                  : ok=39   changed=19   unreachable=0    failed=0    skipped=1    rescued=0    ignored=0  

Configure DNS DKIM and SPF

Get DKIM keys from /etc/opendkim/keys/ on the server.

• Add DKIM record
• Add SPF record e.g. v=spf1 ip4:192.168.1.1 mx ~all
• Add DMARC record e.g. v=DMARC1; p=none; pct=100; fo=1; rua=mailto:[email protected] (use a virtual)

Add user(s)

Note this script is not idempotent.

#!/bin/bash

set -exo pipefail

if [ "$#" -ne 3 ];then
  echo "Usage: $0 DOMAIN USERNAME PASSWORD"
fi

DOMAIN=$1
USERNAME=$2
PASSWORD=$3

MAIL_USER_ID=`id -u mail`

echo Creating mail folder for $USERNAME@$DOMAIN
mkdir -p /var/mail/vhosts/$DOMAIN/$USERNAME

echo Setting mail folder permissions
chown -R mail:mail /var/mail/vhosts/$DOMAIN/$USERNAME

echo Generating password hash
PASSWORD_HASH=`doveadm pw -s SHA512-CRYPT -p $PASSWORD`

echo Adding $USERNAME@$DOMAIN to /etc/dovecot/users file

echo $USERNAME@$DOMAIN:$PASSWORD_HASH:$MAIL_USER_ID:$MAIL_USER_ID::/var/mail/vhosts/$DOMAIN >> /etc/dovecot/users

echo Add vmailbox to postfix
echo $USERNAME@DOMAIN $DOMAIN/$USERNAME >> /etc/postfix/vmailbox

echo Run postmap
postmap /etc/postfix/vmailbox

echo Reload postfix
systemctl reload postfix
echo Reloading dovecot
systemctl reload dovecot.service

Useful resources:

• ipv6 / ipv4 gmail sending https://blog.hqcodeshop.fi/archives/122-Fixing-Googles-new-IPv6-mail-policy-with-Postfix.html

• https://www.linuxbabe.com/mail-server/setting-up-dkim-and-spf

• https://www.linuxbabe.com/mail-server/create-dmarc-record

• https://www.linuxbabe.com/mail-server/setup-basic-postfix-mail-sever-ubuntu

• https://www.linuxbabe.com/mail-server/block-email-spam-check-header-body-with-postfix-spamassassin