diff --git a/common/dns/fakedns/middleware.go b/common/dns/fakedns/middleware.go
index cfc3d18..45021e1 100644
--- a/common/dns/fakedns/middleware.go
+++ b/common/dns/fakedns/middleware.go
@@ -5,13 +5,15 @@ import (
 	"net"
 	"strings"
 
-	trie "github.com/xjasonlyu/tun2socks/common/dns/domain-trie"
 	D "github.com/miekg/dns"
+	"github.com/xjasonlyu/tun2socks/common/cache"
+	trie "github.com/xjasonlyu/tun2socks/common/domain-trie"
+	"github.com/xjasonlyu/tun2socks/common/fakeip"
 )
 
 type handler func(w D.ResponseWriter, r *D.Msg)
 
-func withFakeIP(cache *Cache, pool *Pool) handler {
+func withFakeIP(cache *cache.Cache, pool *fakeip.Pool) handler {
 	return func(w D.ResponseWriter, r *D.Msg) {
 		q := r.Question[0]
 
@@ -88,7 +90,7 @@ func withHost(hosts *trie.Trie, next handler) handler {
 	}
 }
 
-func strToHosts(str string) *trie.Trie {
+func lineToHosts(str string) *trie.Trie {
 	// trim `'` `"` ` ` char
 	str = strings.Trim(str, "' \"")
 	if str == "" {
@@ -110,7 +112,7 @@ func strToHosts(str string) *trie.Trie {
 	return tree
 }
 
-func newHandler(hosts *trie.Trie, cache *Cache, pool *Pool) handler {
+func newHandler(hosts *trie.Trie, cache *cache.Cache, pool *fakeip.Pool) handler {
 	if hosts != nil {
 		return withHost(hosts, withFakeIP(cache, pool))
 	}
diff --git a/common/dns/fakedns/server.go b/common/dns/fakedns/server.go
index 3f46e3d..c80256f 100644
--- a/common/dns/fakedns/server.go
+++ b/common/dns/fakedns/server.go
@@ -7,6 +7,8 @@ import (
 	"time"
 
 	D "github.com/miekg/dns"
+	"github.com/xjasonlyu/tun2socks/common/cache"
+	"github.com/xjasonlyu/tun2socks/common/fakeip"
 )
 
 var (
@@ -18,8 +20,7 @@ var (
 
 type Server struct {
 	*D.Server
-	p *Pool
-	c *Cache
+	c *cache.Cache
 	h handler
 }
 
@@ -65,31 +66,22 @@ func (s *Server) IPToHost(ip net.IP) string {
 	return strings.TrimRight(fqdn, ".")
 }
 
-func (s *Server) IsFakeIP(ip net.IP) bool {
-	c := ip2uint32(ip)
-	if c >= s.p.min && c <= s.p.max {
-		return true
-	}
-	return false
-}
-
-func NewServer(fakeIPRange, hostsMap string) (*Server, error) {
+func NewServer(fakeIPRange, hostsLine string) (*Server, error) {
 	_, ipnet, err := net.ParseCIDR(fakeIPRange)
 	if err != nil {
 		return nil, err
 	}
-	pool, err := NewPool(ipnet)
+	pool, err := fakeip.New(ipnet)
 	if err != nil {
 		return nil, err
 	}
 
-	cache := NewCache(cacheDuration)
-	hosts := strToHosts(hostsMap)
-	handler := newHandler(hosts, cache, pool)
+	hosts := lineToHosts(hostsLine)
+	cacheItem := cache.New(cacheDuration)
+	handler := newHandler(hosts, cacheItem, pool)
 
 	return &Server{
-		p: pool,
-		c: cache,
+		c: cacheItem,
 		h: handler,
 	}, nil
 }
diff --git a/common/dns/fakedns/util.go b/common/dns/fakedns/util.go
index 5b12cbf..c21f6c0 100644
--- a/common/dns/fakedns/util.go
+++ b/common/dns/fakedns/util.go
@@ -6,9 +6,10 @@ import (
 	"time"
 
 	D "github.com/miekg/dns"
+	"github.com/xjasonlyu/tun2socks/common/cache"
 )
 
-func putMsgToCache(c *Cache, key string, msg *D.Msg) {
+func putMsgToCache(c *cache.Cache, key string, msg *D.Msg) {
 	var ttl time.Duration
 	if len(msg.Answer) != 0 {
 		ttl = time.Duration(msg.Answer[0].Header().Ttl) * time.Second