diff --git a/data/conf/postfix/main.cf b/data/conf/postfix/main.cf
index 3157fb73..0990f41c 100644
--- a/data/conf/postfix/main.cf
+++ b/data/conf/postfix/main.cf
@@ -181,6 +181,7 @@ smtp_tls_policy_maps=proxy:mysql:/opt/postfix/conf/sql/mysql_tls_policy_override
 smtp_header_checks = pcre:/opt/postfix/conf/anonymize_headers.pcre
 mail_name = Postcow
 # local_transport map catches local destinations and prevents routing local dests when the next map would route "*"
+# Use custom_transport.pcre for custom transports
 transport_maps = pcre:/opt/postfix/conf/custom_transport.pcre,
   pcre:/opt/postfix/conf/local_transport,
   proxy:mysql:/opt/postfix/conf/sql/mysql_transport_maps.cf