diff --git a/tracemap/tracemap.go b/tracemap/tracemap.go
index 3b3aab0..ed043e8 100644
--- a/tracemap/tracemap.go
+++ b/tracemap/tracemap.go
@@ -23,7 +23,7 @@ func GetMapUrl(r string) (string, error) {
 		if len(strings.Split(fastIp, ":")) > 1 {
 			fastIp = "[" + fastIp + "]"
 		}
-		host = "origin-fallback.nxtrace.org"
+		host = "api.nxtrace.org"
 	} else {
 		// 默认配置完成，开始寻找最优 IP
 		fastIp = util.GetFastIP(host, port, false)
diff --git a/util/latency.go b/util/latency.go
index 51aae07..2d67232 100644
--- a/util/latency.go
+++ b/util/latency.go
@@ -30,7 +30,7 @@ var FastIpCache = ""
 func GetFastIP(domain string, port string, enableOutput bool) string {
 	proxyUrl := GetProxy()
 	if proxyUrl != nil {
-		return "origin-fallback.nxtrace.org"
+		return "api.nxtrace.org"
 	}
 	if FastIpCache != "" {
 		return FastIpCache
@@ -38,7 +38,7 @@ func GetFastIP(domain string, port string, enableOutput bool) string {
 
 	var ips []net.IP
 	var err error
-	if domain == "origin-fallback.nxtrace.org" {
+	if domain == "api.nxtrace.org" {
 		ips, err = net.LookupIP("api.nxtrace.org")
 	} else {
 		ips, err = net.LookupIP(domain)
@@ -122,6 +122,7 @@ func checkLatency(domain string, ip string, port string) {
 		return
 	}
 	req.Host = domain
+	req.Header.Add("User-Agent", UserAgent)
 	resp, err := client.Do(req)
 	if err != nil {
 		//results <- ResponseInfo{IP: ip, Latency: "error", Content: ""}
diff --git a/util/util.go b/util/util.go
index b13929f..2715769 100644
--- a/util/util.go
+++ b/util/util.go
@@ -208,7 +208,7 @@ func GetenvDefault(key, defVal string) string {
 }
 
 func GetHostAndPort() (host string, port string) {
-	var hostP = GetenvDefault("NEXTTRACE_HOSTPORT", "origin-fallback.nxtrace.org")
+	var hostP = GetenvDefault("NEXTTRACE_HOSTPORT", "api.nxtrace.org")
 	// 解析域名
 	hostArr := strings.Split(hostP, ":")
 	// 判断是否有指定端口