diff --git a/smartdns/conf/custom.conf b/smartdns/conf/custom.conf
index e074a3fc..3c4fad4b 100644
--- a/smartdns/conf/custom.conf
+++ b/smartdns/conf/custom.conf
@@ -1,17 +1,5 @@
 # Add custom settings here.
-
-# set log level
-# log-level [level], level=fatal, error, warn, notice, info, debug
-# log-level error
-
-# log-size k,m,g
-# log-size 128k
-
-# log-file /var/log/smartdns.log
-# log-num 2
-
-# List of hosts that supply bogus NX domain results 
-# bogus-nxdomain [ip/subnet]
+# please read https://pymumu.github.io/smartdns/config/basic-config/
 
 speed-check-mode tcp:80,ping