Index: vsftpd-3.0.3/vsftpd.conf
===================================================================
--- vsftpd-3.0.3.orig/vsftpd.conf	2018-06-21 11:01:12.125258812 +0000
+++ vsftpd-3.0.3/vsftpd.conf	2018-06-21 11:04:43.355979116 +0000
@@ -188,8 +188,12 @@ listen=NO
 # Make sure, that one of the listen options is commented !!
 listen_ipv6=YES
 #
-# Set to ssl_enable=YES if you want to enable SSL
+# Set "ssl_enable=YES" to enable SSL support and configure the location of
+# your local certificate (RSA, DSA, or both). Note that vsftpd won't start
+# if either of the "xxx_cert_file" options sets a path that doesn't exist.
 ssl_enable=NO
+rsa_cert_file=
+dsa_cert_file=
 #
 # Limit passive ports to this range to assis firewalling
 pasv_min_port=30000