Prepare skeleton to build a very basic test environment

.gitignore

@@ -1 +1,5 @@
+# Ignore the compiled binary
 mailq-inspector
+
+# Ignore .vagrant folder
+.vagrant

Vagrantfile

@@ -7,7 +7,33 @@ Vagrant.configure("2") do |config|
   config.vm.synced_folder "./", "/vagrant", type: "rsync"
 
   config.vm.provision "shell", inline: <<-SHELL
+    # Basic preparations
     apt-get update
-    apt-get install -y postfix
+
+    # Install postfix
+    DEBIAN_FRONTEND=noninteractive apt-get install -y postfix
+
+    # Enable and launch postfix
+    systemctl enable postfix.service
+    systemctl start postfix.service
+
+    # Block port 25 for IPv4
+    iptables -A INPUT -p tcp --dport 25 -j DROP
+    iptables -A FORWARD -p tcp --dport 25 -j DROP
+    iptables -A OUTPUT -p tcp --dport 25 -j DROP
+
+    # Block port 25 for IPv6
+    ip6tables -A INPUT -p tcp --dport 25 -j DROP
+    ip6tables -A FORWARD -p tcp --dport 25 -j DROP
+    ip6tables -A OUTPUT -p tcp --dport 25 -j DROP
+
+    # Install mailutils (tools to send mail)
+    apt-get install -y mailutils
+
+    # Invoke script that sends test mails, so we have test data
+    /vagrant/vagrant-util/send-test-mails.sh --LETS-REALLY-DO-THIS-AND-SEND-MAIL
+
+    # That's it
+    echo "That's it. We're set up. Enjoy your test environment."
   SHELL
 end

vagrant-util/send-test-mails.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+#
+# This script is supposed to be run within a shielded* vagrant environment.
+# It's job is to send a bunch of test emails, for testing purposes.
+# If you really intend to run this on your own, you need to pass the flag
+# --LETS-REALLY-DO-THIS-AND-SEND-MAIL to it.
+#
+# I don't want this script to do damage.
+if [[ "$1" != "--LETS-REALLY-DO-THIS-AND-SEND-MAIL" ]]; then
+    echo "WORD OF WARNING"
+    echo
+    echo "DO NOT RUN THIS OUT OF A SHIELDED VAGRANT BOX!"
+    echo "TO PROCEED RUNNING THIS TOOL, PROVIDE THE ARGUMENT"
+    echo "--LETS-REALLY-DO-THIS-AND-SEND-MAIL"
+    exit 1;
+fi
+
+echo "LOL" | mail -s "Testmail" jpt@jpt.lu