diff --git a/roles/base/files/postfix/main.cf/main.cf.mailman b/roles/base/files/postfix/main.cf/main.cf.mailman
index f9a0947cb2..14c3d3f434 100644
--- a/roles/base/files/postfix/main.cf/main.cf.mailman
+++ b/roles/base/files/postfix/main.cf/main.cf.mailman
@@ -685,6 +685,7 @@ readme_directory = /usr/share/doc/postfix-2.4.5/README_FILES
 
 
 message_size_limit = 20971520
+inet_protocols = ipv4
 
 
 # Mailman, see MTA.rst
diff --git a/roles/base/files/postfix/main.cf/main.cf.mailman-stg b/roles/base/files/postfix/main.cf/main.cf.mailman-stg
index 75029e2f9d..60ee9ec479 100644
--- a/roles/base/files/postfix/main.cf/main.cf.mailman-stg
+++ b/roles/base/files/postfix/main.cf/main.cf.mailman-stg
@@ -685,6 +685,7 @@ readme_directory = /usr/share/doc/postfix-2.4.5/README_FILES
 
 
 message_size_limit = 20971520
+inet_protocols = ipv4
 
 
 # Mailman, see MTA.rst