diff --git a/roles/mail_server/templates/main.cf.j2 b/roles/mail_server/templates/main.cf.j2
index ca4d07cb3e730101baa5f231602797f37be6c837..0091b0d39ca775ca80f1ef4f819c827c5545e61d 100644
--- a/roles/mail_server/templates/main.cf.j2
+++ b/roles/mail_server/templates/main.cf.j2
@@ -6,7 +6,7 @@
 # ================
 
 # Internet hostname of this mail system.
-myhostname = {{ inventory_hostname }}
+myhostname = {{ ansible_fqdn }}
 
 # Under Debian, when a file name is specified, the first line of the
 # file be used as the SMTP server name.
@@ -49,7 +49,7 @@ compatibility_level = 3.6
 # ======================
 
 # List of domains for local transport deliveries.
-mydestination = {{ inventory_hostname }}, {{ inventory_hostname_short }}, localhost.localdomain, localhost
+mydestination = {{ ansible_fqdn }}, {{ ansible_hostname }}, localhost.localdomain, localhost
 
 # Alias maps for local deliveries (to system accounts).
 alias_maps = hash:/etc/aliases
@@ -111,8 +111,8 @@ smtpd_tls_cert_file = /etc/ssl/certs/{{ ansible_fqdn }}_smtp.pem
 smtpd_tls_key_file = /etc/ssl/private/{{ ansible_fqdn }}_smtp.key
 
 # Use custom, generated DH parameters for increased security.
-smtpd_tls_dh1024_param_file = /etc/ssl/private/{{ inventory_hostname }}_smtp.dh.pem
-smtpd_tls_dh512_param_file = /etc/ssl/private/{{ inventory_hostname }}_smtp.dh.pem
+smtpd_tls_dh1024_param_file = /etc/ssl/private/{{ ansible_fqdn }}_smtp.dh.pem
+smtpd_tls_dh512_param_file = /etc/ssl/private/{{ ansible_fqdn }}_smtp.dh.pem
 
 # Use TLS when available with Postfix SMTP client.
 smtp_tls_security_level = may