diff --git a/cmdeploy/src/cmdeploy/postfix/main.cf.j2 b/cmdeploy/src/cmdeploy/postfix/main.cf.j2
index 8fee07f2..5c624362 100644
--- a/cmdeploy/src/cmdeploy/postfix/main.cf.j2
+++ b/cmdeploy/src/cmdeploy/postfix/main.cf.j2
@@ -64,7 +64,11 @@ alias_database = hash:/etc/aliases
 mydestination =
 
 relayhost = 
+{% if disable_ipv6 %}
+mynetworks = 127.0.0.0/8
+{% else %}
 mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
+{% endif %}
 mailbox_size_limit = 0
 message_size_limit = {{config.max_message_size}}
 recipient_delimiter = +