diff --git a/doh-client/client.go b/doh-client/client.go
index 2f25fa5..1eb30a7 100644
--- a/doh-client/client.go
+++ b/doh-client/client.go
@@ -156,7 +156,7 @@ func (c *Client) handlerFunc(w dns.ResponseWriter, r *dns.Msg, isTCP bool) {
 		return
 	}
 
-	fullReply := jsonDNS.Unmarshal(reply, &respJson, udpSize)
+	fullReply := jsonDNS.Unmarshal(reply, &respJson, udpSize, ednsClientNetmask)
 	buf, err := fullReply.Pack()
 	if err != nil {
 		log.Println(err)
diff --git a/json-dns/unmarshal.go b/json-dns/unmarshal.go
index 73e94cd..7f495ae 100644
--- a/json-dns/unmarshal.go
+++ b/json-dns/unmarshal.go
@@ -42,7 +42,7 @@ func PrepareReply(req *dns.Msg) *dns.Msg {
 	return reply
 }
 
-func Unmarshal(msg *dns.Msg, resp *Response, udpSize uint16) *dns.Msg {
+func Unmarshal(msg *dns.Msg, resp *Response, udpSize uint16, ednsClientNetmask uint8) *dns.Msg {
 	now := time.Now().UTC()
 
 	reply := msg.Copy()
@@ -110,10 +110,17 @@ func Unmarshal(msg *dns.Msg, resp *Response, udpSize uint16) *dns.Msg {
 		}
 	}
 	if ednsClientAddress != nil {
+		if ednsClientNetmask == 255 {
+			if ednsClientFamily == 1 {
+				ednsClientNetmask = 24
+			} else {
+				ednsClientNetmask = 48
+			}
+		}
 		edns0Subnet := new(dns.EDNS0_SUBNET)
         edns0Subnet.Code = dns.EDNS0SUBNET
         edns0Subnet.Family = ednsClientFamily
-        edns0Subnet.SourceNetmask = ednsClientScope
+        edns0Subnet.SourceNetmask = ednsClientNetmask
         edns0Subnet.SourceScope = ednsClientScope
         edns0Subnet.Address = ednsClientAddress
         opt.Option = append(opt.Option, edns0Subnet)