diff --git a/conf.go b/conf.go
index a288cbd..c6ff75d 100644
--- a/conf.go
+++ b/conf.go
@@ -44,10 +44,6 @@ func loadConfig(f string) (*conf, error) {
 		return nil, err
 	}
 
-	if c.Debug {
-		logLevel = DEBUG
-	}
-
 	if c.blacklist == nil {
 		c.blacklist = item{}
 	}
diff --git a/handler.go b/handler.go
index e8fab4f..ec54514 100644
--- a/handler.go
+++ b/handler.go
@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/fangdingjun/go-log"
 	"github.com/miekg/dns"
 )
 
@@ -69,28 +70,28 @@ func (h *dnsHandler) queryUpstream(r *dns.Msg, srv addr, ch chan *dns.Msg) {
 
 	switch srv.Network {
 	case "tcp":
-		info("query %s IN %s, forward to %s:%d through tcp",
+		log.Debugf("query %s IN %s, forward to %s:%d through tcp",
 			r.Question[0].Name,
 			dns.TypeToString[r.Question[0].Qtype],
 			srv.Host,
 			srv.Port)
 		m, _, err = h.tcpclient.Exchange(r, fmt.Sprintf("%s:%d", srv.Host, srv.Port))
 	case "udp":
-		info("query %s IN %s, forward to %s:%d through udp",
+		log.Debugf("query %s IN %s, forward to %s:%d through udp",
 			r.Question[0].Name,
 			dns.TypeToString[r.Question[0].Qtype],
 			srv.Host,
 			srv.Port)
 		m, _, err = h.udpclient.Exchange(r, fmt.Sprintf("%s:%d", srv.Host, srv.Port))
 	case "https_google":
-		info("query %s IN %s, forward to %s:%d through google https",
+		log.Debugf("query %s IN %s, forward to %s:%d through google https",
 			r.Question[0].Name,
 			dns.TypeToString[r.Question[0].Qtype],
 			srv.Host,
 			srv.Port)
 		m, _, err = h.httpsgoogle.Exchange(r, fmt.Sprintf("%s:%d", srv.Host, srv.Port))
 	case "https_cloudflare":
-		info("query %s IN %s, forward to %s:%d through cloudflare https",
+		log.Debugf("query %s IN %s, forward to %s:%d through cloudflare https",
 			r.Question[0].Name,
 			dns.TypeToString[r.Question[0].Qtype],
 			srv.Host,
@@ -106,7 +107,7 @@ func (h *dnsHandler) queryUpstream(r *dns.Msg, srv addr, ch chan *dns.Msg) {
 		default:
 		}
 	} else {
-		errorlog("%s", err)
+		log.Errorf("%s", err)
 	}
 }
 
@@ -130,7 +131,7 @@ func (h *dnsHandler) getAnswerFromUpstream(r *dns.Msg, servers []addr) (*dns.Msg
 			if savedErr != nil {
 				return savedErr, nil
 			}
-			info("query %s IN %s, timeout", r.Question[0].Name, dns.TypeToString[r.Question[0].Qtype])
+			log.Debugf("query %s IN %s, timeout", r.Question[0].Name, dns.TypeToString[r.Question[0].Qtype])
 			return nil, errors.New("timeout")
 		}
 	}
@@ -147,7 +148,7 @@ func (h *dnsHandler) inBlacklist(m *dns.Msg) bool {
 			ip = ""
 		}
 		if ip != "" && h.cfg.blacklist.exists(ip) {
-			info("%s in blacklist", ip)
+			log.Debugf("%s in blacklist", ip)
 			return true
 		}
 	}
@@ -168,7 +169,7 @@ func (h *dnsHandler) answerFromHosts(w dns.ResponseWriter, r *dns.Msg) bool {
 		msg.SetReply(r)
 		msg.Answer = append(msg.Answer, rr)
 		w.WriteMsg(msg)
-		info("query %s IN %s, reply from hosts", domain, dns.TypeToString[t])
+		log.Debugf("query %s IN %s, reply from hosts", domain, dns.TypeToString[t])
 		return true
 	}
 	return false
diff --git a/log.go b/log.go
deleted file mode 100644
index 7592c4f..0000000
--- a/log.go
+++ /dev/null
@@ -1,31 +0,0 @@
-package main
-
-import (
-	"log"
-)
-
-const (
-	_ = iota
-	FATAL
-	ERROR
-	WARN
-	NOTICE
-	INFO
-	DEBUG
-)
-
-var logLevel = WARN
-
-func logMsg(l int, fmt string, args ...interface{}) {
-	if l <= logLevel {
-		log.Printf(fmt, args...)
-	}
-}
-
-func info(fmt string, args ...interface{}) {
-	logMsg(INFO, fmt, args...)
-}
-
-func errorlog(fmt string, args ...interface{}) {
-	logMsg(ERROR, fmt, args...)
-}
diff --git a/server.go b/server.go
index fe4ad24..55d4ff4 100644
--- a/server.go
+++ b/server.go
@@ -3,26 +3,59 @@ package main
 import (
 	"flag"
 	"fmt"
-	"log"
+	"os"
 
+	"github.com/fangdingjun/go-log"
+	"github.com/fangdingjun/go-log/formatters"
+	"github.com/fangdingjun/go-log/writers"
 	"github.com/miekg/dns"
 )
 
 func main() {
 	var configfile string
+	var logfile string
+	var loglevel string
+	var logFileSize int64
+	var logFileCount int
 
 	flag.StringVar(&configfile, "c", "config.yaml", "config file")
+	flag.StringVar(&logfile, "log_file", "", "log file, default stdout")
+	flag.IntVar(&logFileCount, "log_count", 10, "max count of log to keep")
+	flag.Int64Var(&logFileSize, "log_size", 10, "max log file size MB")
+	flag.StringVar(&loglevel, "log_level", "INFO", "log level, values:\nOFF, FATAL, PANIC, ERROR, WARN, INFO, DEBUG")
 	flag.Parse()
 
+	if logfile != "" {
+		log.Default.Out = &writers.FixedSizeFileWriter{
+			MaxCount: logFileCount,
+			Name:     logfile,
+			MaxSize:  logFileSize * 1024 * 1024,
+		}
+	}
+
+	if loglevel != "" {
+		lv, err := log.ParseLevel(loglevel)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		log.Default.Level = lv
+	}
+
+	log.Default.Formatter = &formatters.TextFormatter{TimeFormat: "2006-01-02 15:04:05.000"}
+
 	config, err := loadConfig(configfile)
 	if err != nil {
 		log.Fatal(err)
 	}
 
+	log.Debugf("config: %+v", config)
+
 	h := newDNSHandler(config)
 
 	for _, l := range config.Listen {
 		go func(l addr) {
+			log.Infof("listen on %s %s:%d", l.Network, l.Host, l.Port)
 			if err := dns.ListenAndServe(
 				fmt.Sprintf("%s:%d", l.Host, l.Port), l.Network, h); err != nil {
 				log.Fatal(err)