diff --git a/node/conn.go b/node/conn.go
index 0a03c22..fbc16f8 100644
--- a/node/conn.go
+++ b/node/conn.go
@@ -60,17 +60,21 @@ func (w *connWriter) WriteTo(remoteIP, packetType byte, data []byte) error {
 
 type connReader struct {
 	*net.UDPConn
-	localIP  byte
-	counters [256]uint64
-	lookup   func(byte) *peer
+	localIP   byte
+	dupChecks [256]*dupCheck
+	lookup    func(byte) *peer
 }
 
 func newConnReader(conn *net.UDPConn, localIP byte, lookup func(byte) *peer) *connReader {
-	return &connReader{
+	r := &connReader{
 		UDPConn: conn,
 		localIP: localIP,
 		lookup:  lookup,
 	}
+	for i := range r.dupChecks {
+		r.dupChecks[i] = newDupCheck(0)
+	}
+	return r
 }
 
 func (r *connReader) Read(buf []byte) (remoteAddr netip.AddrPort, h header, data []byte, err error) {
@@ -94,8 +98,8 @@ func (r *connReader) Read(buf []byte) (remoteAddr netip.AddrPort, h header, data
 			continue // Packet is corrupt.
 		}
 
-		if h.Counter > r.counters[h.SourceIP] {
-			r.counters[h.SourceIP] = h.Counter
+		if r.dupChecks[h.SourceIP].IsDup(h.Counter) {
+			continue
 		}
 
 		return