diff --git a/setup/flavors/compose/mailu.env b/setup/flavors/compose/mailu.env
index 78ecce72..b3cef48d 100644
--- a/setup/flavors/compose/mailu.env
+++ b/setup/flavors/compose/mailu.env
@@ -76,8 +76,8 @@ FETCHMAIL_DELAY={{ fetchmail_delay or '600' }}
 RECIPIENT_DELIMITER={{ recipient_delimiter or '+' }}
 
 # DMARC rua and ruf email
-DMARC_RUA={{ dmarc_rua or 'admin' }}
-DMARC_RUF={{ dmarc_ruf or 'admin' }}
+DMARC_RUA={{ dmarc_rua or postmaster }}
+DMARC_RUF={{ dmarc_ruf or postmaster }}
 
 # Welcome email, enable and set a topic and body if you wish to send welcome
 # emails to all users.
diff --git a/towncrier/newsfragments/1463.bugfix b/towncrier/newsfragments/1463.bugfix
new file mode 100644
index 00000000..37423bfa
--- /dev/null
+++ b/towncrier/newsfragments/1463.bugfix
@@ -0,0 +1 @@
+Defining POSTMASTER through setup tool apply also to DMARC_RUA and DMARC_RUF settings