diff --git a/target/postfix/main.cf b/target/postfix/main.cf
index d501eec0..518e2dc5 100644
--- a/target/postfix/main.cf
+++ b/target/postfix/main.cf
@@ -68,9 +68,10 @@ smtpd_forbid_bare_newline = yes
 # smtpd_forbid_bare_newline_exclusions = $mynetworks
 
 # Custom defined parameters for DMS:
-# reject_unknown_sender_domain: https://github.com/docker-mailserver/docker-mailserver/issues/3716#issuecomment-1868033234
+# Custom sender restrictions overview: https://github.com/docker-mailserver/docker-mailserver/pull/4379#issuecomment-2670365917
+# `reject_unknown_sender_domain`: https://github.com/docker-mailserver/docker-mailserver/issues/3716#issuecomment-1868033234
 dms_smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unknown_sender_domain
-# Submission ports 587 and 465 support for SPOOF_PROTECTION=1
+# `SPOOF_PROTECTION=1` support requires prepending `reject_authenticated_sender_login_mismatch`
 mua_sender_restrictions = reject_authenticated_sender_login_mismatch, $dms_smtpd_sender_restrictions
 
 # Postscreen settings to drop zombies/open relays/spam early
diff --git a/target/scripts/startup/setup.d/postfix.sh b/target/scripts/startup/setup.d/postfix.sh
index e99e6607..9e9370ab 100644
--- a/target/scripts/startup/setup.d/postfix.sh
+++ b/target/scripts/startup/setup.d/postfix.sh
@@ -93,13 +93,17 @@ EOF
 function _setup_postfix_late() {
   _log 'debug' 'Configuring Postfix (late setup)'
 
+  # These two config files are `access` database tables managed via `setup email restrict`:
+  # NOTE: Prepends to existing restrictions, thus has priority over other permit/reject policies that follow.
+  # https://www.postfix.org/postconf.5.html#smtpd_sender_restrictions
+  # https://www.postfix.org/access.5.html
   __postfix__log 'trace' 'Configuring user access'
   if [[ -f /tmp/docker-mailserver/postfix-send-access.cf ]]; then
-    sed -i -E 's|(smtpd_sender_restrictions =)|\1 check_sender_access texthash:/tmp/docker-mailserver/postfix-send-access.cf,|' /etc/postfix/main.cf
+    sed -i -E 's|^(dms_smtpd_sender_restrictions =)|\1 check_sender_access texthash:/tmp/docker-mailserver/postfix-send-access.cf,|' /etc/postfix/main.cf
   fi
 
   if [[ -f /tmp/docker-mailserver/postfix-receive-access.cf ]]; then
-    sed -i -E 's|(smtpd_recipient_restrictions =)|\1 check_recipient_access texthash:/tmp/docker-mailserver/postfix-receive-access.cf,|' /etc/postfix/main.cf
+    sed -i -E 's|^(dms_smtpd_recipient_restrictions =)|\1 check_recipient_access texthash:/tmp/docker-mailserver/postfix-receive-access.cf,|' /etc/postfix/main.cf
   fi
 
   __postfix__log 'trace' 'Configuring relay host'