diff --git a/conf/main_ipv4.conf.sample b/conf/main_ipv4.conf.sample
index 60de004..f3dff5d 100644
--- a/conf/main_ipv4.conf.sample
+++ b/conf/main_ipv4.conf.sample
@@ -239,6 +239,10 @@ ntp_allowed_net=""
 dhcp_server_ifs=""
 
 # - DNS Server 
+# -
+# - Note:
+# -    leave empty if you support only DNS Resolver Service
+# -
 dns_server_ips=""
 forward_dns_server_ips=""
 
@@ -258,6 +262,9 @@ resolver_port="$standard_dns_port"
 # - Example:
 # -    resolver_allowed_networks="192.68.11.64/27 194.150.169.139"
 # -
+# -    # Open DNS Resolver
+# -    resolver_allowed_net="0.0.0.0/0"
+# -
 resolver_allowed_networks=""
 
 
diff --git a/conf/main_ipv6.conf.sample b/conf/main_ipv6.conf.sample
index 4ce52be..6760006 100644
--- a/conf/main_ipv6.conf.sample
+++ b/conf/main_ipv6.conf.sample
@@ -255,6 +255,10 @@ ntp_allowed_net=""
 dhcp_server_ifs=""
 
 # - DNS Server 
+# -
+# - Note:
+# -    leave empty if you support only DNS Resolver Service
+# -
 dns_server_ips=""
 forward_dns_server_ips=""
 
@@ -274,6 +278,9 @@ resolver_port="$standard_dns_port"
 # - Example:
 # -    resolver_allowed_net="2001:678:a40:3000::/64 2001:678:a40:4000::/64"
 # -
+# -    # Open DNS Resolver
+# -    resolver_allowed_net="::/0"
+# -
 resolver_allowed_networks=""