diff --git a/libexec/dma/dmagent/mailer.conf b/libexec/dma/dmagent/mailer.conf
--- a/libexec/dma/dmagent/mailer.conf
+++ b/libexec/dma/dmagent/mailer.conf
@@ -1,4 +1,9 @@
 # $FreeBSD$
+#
+# mailer.conf for use with dma(8)
+#
+# If sendmail is configured, an example of mailer.conf that uses sendmail
+# instead can be found in /usr/share/examples/sendmail.
 
 sendmail	/usr/libexec/dma
 mailq		/usr/libexec/dma