diff --git a/conn/bind_windows.go b/conn/bind_windows.go
index 6cabee1..a25c7aa 100644
--- a/conn/bind_windows.go
+++ b/conn/bind_windows.go
@@ -47,7 +47,7 @@ func (rb *ringBuffer) Push() *ringPacket {
 	}
 	ret := (*ringPacket)(unsafe.Pointer(rb.packets + (uintptr(rb.tail%packetsPerRing) * unsafe.Sizeof(ringPacket{}))))
 	rb.tail += 1
-	if rb.tail == rb.head {
+	if rb.tail%packetsPerRing == rb.head%packetsPerRing {
 		rb.isFull = true
 	}
 	return ret