diff --git a/common/dns/dns.go b/common/dns/dns.go
index 4b3ce20..ce8994b 100644
--- a/common/dns/dns.go
+++ b/common/dns/dns.go
@@ -6,15 +6,6 @@ import (
 
 const CommonDnsPort = 53
 
-type DnsCache interface {
-	// Query queries the response for the DNS request with payload `p`,
-	// the response data should be a valid DNS response payload.
-	Query(p []byte) []byte
-
-	// Store stores the DNS response with payload `p` to the cache.
-	Store(p []byte)
-}
-
 type FakeDns interface {
 	// GenerateFakeResponse generates a fake dns response for the specify request.
 	// GenerateFakeResponse(request []byte) ([]byte, error)
@@ -23,5 +14,5 @@ type FakeDns interface {
 	IPToHost(ip net.IP) string
 
 	// IsFakeIP checks if the given ip is a fake IP.
-	IsFakeIP(ip net.IP) bool
+	// IsFakeIP(ip net.IP) bool
 }