Split postfix configs across the VMs, and start making them do things

Vagrantfile

@@ -10,10 +10,12 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.define "sender" do |sender|
     sender.vm.network "private_network", ip: "192.168.33.5"
     sender.vm.hostname = "sender.example.com"
+    config.vm.synced_folder "vm-postfix-config-sender", "/etc/postfix"
   end
   config.vm.define "valid" do |valid|
     valid.vm.network "private_network", ip: "192.168.33.7"
     valid.vm.hostname = "valid-example-recipient.com"
+    config.vm.synced_folder "vm-postfix-config-valid", "/etc/postfix"
   end
   config.vm.provision :shell, path: "vagrant-bootstrap.sh"
 
@@ -22,5 +24,4 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
      vb.customize ["modifyvm", :id, "--memory", "256"]
   end
 
-  config.vm.synced_folder "vm-postfix-config", "/etc/postfix"
 end

vm-postfix-config-sender/main.cf

@@ -39,4 +39,4 @@ recipient_delimiter = +
 inet_interfaces = all
 
 #STARTTLS EVERYWHERE MAGIC STARTS HERE
-smtp_tls_policy_maps = hash:/etc/postfix/tls_policy
+smtp_tls_policy_maps = texthash:/etc/postfix/tls_policy

vm-postfix-config-sender/tls_policy

@@ -0,0 +1 @@
+valid-example-recipient.com encrypt protocols=TLSv1.2

vm-postfix-config/tls_policy

@@ -1 +0,0 @@
-valid-example-recipient.com encrypt