diff --git a/public/fs/etc/postfix/main.cf.in b/public/fs/etc/postfix/main.cf.in
index 6163967..60cf63d 100644
--- a/public/fs/etc/postfix/main.cf.in
+++ b/public/fs/etc/postfix/main.cf.in
@@ -65,6 +65,13 @@ smtpd_tls_CAfile                = /etc/easy-rsa/pki/ca.crt
 smtpd_relay_restrictions        = permit_mynetworks, permit_tls_all_clientcerts, reject_unauth_destination
 smtpd_recipient_restrictions    = permit_mynetworks, permit_tls_all_clientcerts, reject_unauth_destination
 
+smtpd_helo_required             = yes
+smtpd_helo_restrictions         = permit_mynetworks,
+	                          permit_tls_all_clientcerts,
+	                          reject_invalid_helo_hostname,
+	                          reject_unknown_helo_hostname,
+	                          reject_non_fqdn_helo_hostname
+
 meta_directory                  = /usr/lib/postfix
 setgid_group                    = maildrop
 newaliases_path                 = /usr/bin/newaliases