diff --git a/README.md b/README.md
index ceee7e5..c4e2c81 100644
--- a/README.md
+++ b/README.md
@@ -119,6 +119,8 @@ glider v0.6.7 usage:
         config file path
   -dns string
         dns forwarder server listen address
+  -dnsalwaystcp
+        always use tcp to query upstream dns servers no matter there is a forwarder or not
   -dnsmaxttl int
         maximum TTL value for entries in the CACHE(seconds) (default 1800)
   -dnsminttl int
diff --git a/conf.go b/conf.go
index 5929f9d..c3f855d 100644
--- a/conf.go
+++ b/conf.go
@@ -50,8 +50,8 @@ func confInit() {
 	flag.StringVar(&conf.RulesDir, "rules-dir", "", "rule file folder")
 
 	flag.StringVar(&conf.DNS, "dns", "", "dns forwarder server listen address")
-	flag.BoolVar(&conf.DNSConfig.AlwaysTCP, "dnsalwaystcp", false, "always use tcp to query upstream dns servers no matter there's a forwarder or not")
 	flag.StringSliceUniqVar(&conf.DNSConfig.Servers, "dnsserver", []string{"8.8.8.8:53"}, "remote dns server")
+	flag.BoolVar(&conf.DNSConfig.AlwaysTCP, "dnsalwaystcp", false, "always use tcp to query upstream dns servers no matter there is a forwarder or not")
 	flag.IntVar(&conf.DNSConfig.Timeout, "dnstimeout", 3, "timeout value used in multiple dnsservers switch(seconds)")
 	flag.IntVar(&conf.DNSConfig.MaxTTL, "dnsmaxttl", 1800, "maximum TTL value for entries in the CACHE(seconds)")
 	flag.IntVar(&conf.DNSConfig.MinTTL, "dnsminttl", 0, "minimum TTL value for entries in the CACHE(seconds)")
diff --git a/config/glider.conf.example b/config/glider.conf.example
index ae20836..701d33e 100644
--- a/config/glider.conf.example
+++ b/config/glider.conf.example
@@ -128,15 +128,25 @@ checkduration=30
 
 # Setup a dns forwarding server
 dns=:53
+
 # global remote dns server (you can specify different dns server in rule file)
 dnsserver=8.8.8.8:53
 dnsserver=1.1.1.1:53
+
+# By default, when glider received udp dns request and there's no forwarder specified, 
+# it will use udp to query upstream dns servers, otherwise, use tcp;
+# you can set dnsalwaystcp=true to always use tcp no matter there is a forwarder or not.
+# dnsalwaystcp=false
+
 # timeout value used in multiple dnsservers switch(seconds)
 dnstimeout=3
+
 # maximum TTL value for entries in the CACHE(seconds)
 dnsmaxttl=1800
+
 # minimum TTL value for entries in the CACHE(seconds)
 dnsminttl=0
+
 # custom records
 dnsrecord=www.example.com/1.2.3.4
 dnsrecord=www.example.com/2606:2800:220:1:248:1893:25c8:1946