diff --git a/optional/postgresql/conf/pg_hba.conf b/optional/postgresql/conf/pg_hba.conf
index a45aefc6..fdf82644 100644
--- a/optional/postgresql/conf/pg_hba.conf
+++ b/optional/postgresql/conf/pg_hba.conf
@@ -82,7 +82,7 @@ local   all             all                                     peer map=local
 host    mailu           mailu           {{ SUBNET }}            md5
 host    postgres        health          127.0.0.1/32            trust
 # IPv6 local connections:
-host    mailu           mailu           {{ SUBNET6 }}           md5
+host    mailu           mailu           {{ SUBNET6|default('::1/128') }}    md5
 host    all             all             ::1/128                 reject
 # Allow replication connections from localhost, by a user with the
 # replication privilege.
diff --git a/towncrier/newsfragments/1479.bug b/towncrier/newsfragments/1479.bug
new file mode 100644
index 00000000..7144a98e
--- /dev/null
+++ b/towncrier/newsfragments/1479.bug
@@ -0,0 +1 @@
+Allow IPv6 authenticated connections in PostgreSQL pg_hba.conf
\ No newline at end of file