diff --git a/vh_le.conf b/vh_le.conf
index 2cd306d..37f6b97 100644
--- a/vh_le.conf
+++ b/vh_le.conf
@@ -11,7 +11,9 @@ sub = ['test']
 # the IPv6
 ip6_back = "2001:0912:3064:XXXX"
 
-# the main zone record without extension
+# FQDN of the front web server, as stated in DNS zone, without the tld
+# It will only be used for checking the DNS validity
+# i.e. "merlin.hadoly"
 main_zone = "merlin.hadoly"