diff --git a/.circleci/config.yml b/.circleci/config.yml
index 510eacc..da7e498 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -13,17 +13,21 @@ jobs:
             cp deploy/* .
             mkdir artifacts
       - run:
-          name: build linux Binary
+          name: Run Unit Test
+          command: |
+            make test
+      - run:
+          name: Build linux Binary
           command: |
             make build
             tar czvf artifacts/sower_linux_amd64.tar.gz sower sower.toml sower-client.service sower-server.service
       - run:
-          name: build macOS Binary
+          name: Build macOS Binary
           command: |
             GOOS=darwin GOARCH=amd64 make build
             tar czvf artifacts/sower_darwin_amd64.tar.gz sower sower.toml cc.wweir.sower.plist
       - run:
-          name: build Windows Binary
+          name: Build Windows Binary
           command: |
             GOOS=windows GOARCH=amd64 make build
             tar czvf artifacts/sower_windows_amd64.tar.gz sower sower.toml
@@ -38,7 +42,7 @@ jobs:
               ghr -t ${GITHUB_TOKEN} -u ${CIRCLE_PROJECT_USERNAME} -r ${CIRCLE_PROJECT_REPONAME} -c ${CIRCLE_SHA1} -delete ${VERSION%-*-*} artifacts/
             fi
       - run:
-          name: build docker image
+          name: Build Docker Image
           command: |
             if git log -1 --pretty='%s' | grep -oE '(^|\s)@release(\s|$)'; then
               docker login -u $DOCKER_USER -p $DOCKER_PASS
diff --git a/conf/sower.toml b/conf/sower.toml
index 6ef9197..ffb55c1 100644
--- a/conf/sower.toml
+++ b/conf/sower.toml
@@ -28,6 +28,8 @@ blocklist=[
     "**.amazon.com",
     "**.amazonaws.com",
     "*.githubusercontent.com",
+    "*.github.com",
+    "*.github.io",
     "**.mozilla.com",
     "**.mozilla.net",
     "**.akadns.net",
diff --git a/dns/dns.go b/dns/dns.go
index d486316..e70298c 100644
--- a/dns/dns.go
+++ b/dns/dns.go
@@ -27,7 +27,7 @@ func StartDNS(dnsServer, listenIP string) {
 		go func() {
 			for {
 				<-dhcpCh
-				host := GetDefaultDNSServer()
+				host := util.GetDefaultDNSServer()
 				if host == "" {
 					continue
 				}
diff --git a/go.mod b/go.mod
index 34cb833..9fc5d9d 100644
--- a/go.mod
+++ b/go.mod
@@ -6,11 +6,11 @@ require (
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
 	github.com/hashicorp/golang-lru v0.5.0 // indirect
 	github.com/klauspost/cpuid v1.2.0 // indirect
-	github.com/klauspost/reedsolomon v1.8.0 // indirect
+	github.com/klauspost/reedsolomon v1.9.0 // indirect
 	github.com/lucas-clemente/aes12 v0.0.0-20171027163421-cd47fb39b79f // indirect
 	github.com/lucas-clemente/quic-go v0.10.1
 	github.com/lucas-clemente/quic-go-certificates v0.0.0-20160823095156-d2f86524cced // indirect
-	github.com/miekg/dns v1.1.3
+	github.com/miekg/dns v1.1.4
 	github.com/pelletier/go-toml v1.2.0
 	github.com/pkg/errors v0.8.1
 	github.com/templexxx/cpufeat v0.0.0-20180724012125-cef66df7f161 // indirect
@@ -21,7 +21,7 @@ require (
 	github.com/wweir/mem-go v0.0.0-20190109100331-8673ab596296
 	github.com/wweir/netboot v0.0.2
 	github.com/xtaci/kcp-go v5.0.7+incompatible
-	golang.org/x/crypto v0.0.0-20190123085648-057139ce5d2b
-	golang.org/x/net v0.0.0-20190125091013-d26f9f9a57f3 // indirect
-	golang.org/x/sys v0.0.0-20190124100055-b90733256f2e // indirect
+	golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67
+	golang.org/x/net v0.0.0-20190213061140-3a22650c66bd // indirect
+	golang.org/x/sys v0.0.0-20190213121743-983097b1a8a3 // indirect
 )
diff --git a/go.sum b/go.sum
index 28c24a9..1ca7d57 100644
--- a/go.sum
+++ b/go.sum
@@ -8,16 +8,16 @@ github.com/hashicorp/golang-lru v0.5.0 h1:CL2msUPvZTLb5O648aiLNJw3hnBxN2+1Jq8rCO
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/klauspost/cpuid v1.2.0 h1:NMpwD2G9JSFOE1/TJjGSo5zG7Yb2bTe7eq1jH+irmeE=
 github.com/klauspost/cpuid v1.2.0/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
-github.com/klauspost/reedsolomon v1.8.0 h1:lvvOkvk64cE1EGbBIgFk7WSOOsI1GexpuLiT7zjab6g=
-github.com/klauspost/reedsolomon v1.8.0/go.mod h1:CwCi+NUr9pqSVktrkN+Ondf06rkhYZ/pcNv7fu+8Un4=
+github.com/klauspost/reedsolomon v1.9.0 h1:usyTY5K7D2B6WOHn2jmpB7ky8Qom96mShZmmq3OW4JU=
+github.com/klauspost/reedsolomon v1.9.0/go.mod h1:CwCi+NUr9pqSVktrkN+Ondf06rkhYZ/pcNv7fu+8Un4=
 github.com/lucas-clemente/aes12 v0.0.0-20171027163421-cd47fb39b79f h1:sSeNEkJrs+0F9TUau0CgWTTNEwF23HST3Eq0A+QIx+A=
 github.com/lucas-clemente/aes12 v0.0.0-20171027163421-cd47fb39b79f/go.mod h1:JpH9J1c9oX6otFSgdUHwUBUizmKlrMjxWnIAjff4m04=
 github.com/lucas-clemente/quic-go v0.10.1 h1:ipcMmYP9RT+b1YytOKGUY1qndxPGOczVEQkAVz3CZrs=
 github.com/lucas-clemente/quic-go v0.10.1/go.mod h1:wuD+2XqEx8G9jtwx5ou2BEYBsE+whgQmlj0Vz/77PrY=
 github.com/lucas-clemente/quic-go-certificates v0.0.0-20160823095156-d2f86524cced h1:zqEC1GJZFbGZA0tRyNZqRjep92K5fujFtFsu5ZW7Aug=
 github.com/lucas-clemente/quic-go-certificates v0.0.0-20160823095156-d2f86524cced/go.mod h1:NCcRLrOTZbzhZvixZLlERbJtDtYsmMw8Jc4vS8Z0g58=
-github.com/miekg/dns v1.1.3 h1:1g0r1IvskvgL8rR+AcHzUA+oFmGcQlaIm4IqakufeMM=
-github.com/miekg/dns v1.1.3/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
+github.com/miekg/dns v1.1.4 h1:rCMZsU2ScVSYcAsOXgmC6+AKOK+6pmQTOcw03nfwYV0=
+github.com/miekg/dns v1.1.4/go.mod h1:W1PPwlIAgtquWBMBEV9nkV9Cazfe8ScdGz/Lj7v3Nrg=
 github.com/pelletier/go-toml v1.2.0 h1:T5zMGML61Wp+FlcbWjRDT7yAxhJNAiPPLOFECq181zc=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
@@ -38,9 +38,9 @@ github.com/wweir/netboot v0.0.2 h1:DFuNd97kxzgblExEKn4Nqf1du0m9qUnaTQ70rFgIjLU=
 github.com/wweir/netboot v0.0.2/go.mod h1:p/WOnPHdqwgAI6YLEfdmwjwutbc/zDZ7EojAHlXLi4s=
 github.com/xtaci/kcp-go v5.0.7+incompatible h1:zs9tc8XRID0m+aetu3qPWZFyRt2UIMqbXIBgw+vcnlE=
 github.com/xtaci/kcp-go v5.0.7+incompatible/go.mod h1:bN6vIwHQbfHaHtFpEssmWsN45a+AZwO7eyRCmEIbtvE=
-golang.org/x/crypto v0.0.0-20190123085648-057139ce5d2b h1:Elez2XeF2p9uyVj0yEUDqQ56NFcDtcBNkYP7yv8YbUE=
-golang.org/x/crypto v0.0.0-20190123085648-057139ce5d2b/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
-golang.org/x/net v0.0.0-20190125091013-d26f9f9a57f3 h1:ulvT7fqt0yHWzpJwI57MezWnYDVpCAYBVuYst/L+fAY=
-golang.org/x/net v0.0.0-20190125091013-d26f9f9a57f3/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/sys v0.0.0-20190124100055-b90733256f2e h1:3GIlrlVLfkoipSReOMNAgApI0ajnalyLa/EZHHca/XI=
-golang.org/x/sys v0.0.0-20190124100055-b90733256f2e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67 h1:ng3VDlRp5/DHpSWl02R4rM9I+8M2rhmsuLwAMmkLQWE=
+golang.org/x/crypto v0.0.0-20190211182817-74369b46fc67/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/net v0.0.0-20190213061140-3a22650c66bd h1:HuTn7WObtcDo9uEEU7rEqL0jYthdXAmZ6PP+meazmaU=
+golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sys v0.0.0-20190213121743-983097b1a8a3 h1:+KlxhGbYkFs8lMfwKn+2ojry1ID5eBSMXprS2u/wqCE=
+golang.org/x/sys v0.0.0-20190213121743-983097b1a8a3/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
diff --git a/dns/dhcp.go b/util/dhcp.go
similarity index 90%
rename from dns/dhcp.go
rename to util/dhcp.go
index 9d8f34d..636d1d4 100644
--- a/dns/dhcp.go
+++ b/util/dhcp.go
@@ -1,8 +1,9 @@
-package dns
+package util
 
 import (
 	"math/rand"
 	"net"
+	"runtime"
 
 	"github.com/golang/glog"
 	"github.com/wweir/netboot/dhcp4"
@@ -19,9 +20,14 @@ func GetDefaultDNSServer() string {
 		dhcp4.OptRequestedOptions: []byte{byte(dhcp4.OptDNSServers)},
 	}
 
+	NewConn := dhcp4.NewConn
+	if runtime.GOOS == "linux" {
+		NewConn = dhcp4.NewSnooperConn
+	}
+
 	ifaces := mustGetInterfaces()
 	for _, iface := range ifaces {
-		conn, err := dhcp4.NewConn(iface.IP.String() + ":68")
+		conn, err := NewConn(iface.IP.String() + ":68")
 		if err != nil { // maybe in use
 			glog.V(1).Infoln(err)
 			continue
diff --git a/dns/dhcp_test.go b/util/dhcp_test.go
similarity index 51%
rename from dns/dhcp_test.go
rename to util/dhcp_test.go
index 18b9a8b..8538e6f 100644
--- a/dns/dhcp_test.go
+++ b/util/dhcp_test.go
@@ -1,20 +1,19 @@
-package dns
+package util
 
 import "testing"
 
 func TestGetDefaultDNSServer(t *testing.T) {
-	t.Skip("for net env")
+	t.Skip("skip for some enviroment not support dhcp")
+
 	tests := []struct {
 		name string
-		want string
 	}{{
 		"",
-		"192.168.1.1",
 	}}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := GetDefaultDNSServer(); got != tt.want {
-				t.Errorf("GetDefaultDNSServer() = %v, want %v", got, tt.want)
+			if got := GetDefaultDNSServer(); got == "" {
+				t.Errorf("GetDefaultDNSServer() return empty")
 			}
 		})
 	}