diff --git a/conf/sower.toml b/conf/sower.toml
index 0ccfad1..f5f2699 100644
--- a/conf/sower.toml
+++ b/conf/sower.toml
@@ -4,7 +4,7 @@ password="12345678"
 server_port="5533"
 # server_addr="remote-server"   # replce it to remote server
 http_proxy=":8080"              # eg: 192.168.0.2:8080
-dns_server=""                   # eg: 113.5.5.5:53, Keep empty for dynamic setting from net env
+dns_server=""                   # eg: 223.5.5.5:53, Keep empty for dynamic setting from net env
 client_ip="127.0.0.1"           # listen the IP, dns target is the IP
 # clear_dns_cache="pkill mDNSResponder || true"   # Windows: "ipconfig /flushdnss"
 suggest_level="SPEEDUP"         # DISABLE, BLOCK, SPEEDUP
diff --git a/dns/dns.go b/dns/dns.go
index cacc7b2..7541715 100644
--- a/dns/dns.go
+++ b/dns/dns.go
@@ -23,7 +23,7 @@ func StartDNS(dnsServer, listenIP string, suggestCh chan<- string, level string)
 
 	dhcpCh := make(chan struct{})
 	if dnsServer != "" {
-		if !strings.ContainsRune(dnsServer, ':') {
+		if _, _, err := net.SplitHostPort(dnsServer); err != nil {
 			dnsServer = net.JoinHostPort(dnsServer, "53")
 		}
 	} else {