diff --git a/ackhandler/received_packet_handler.go b/ackhandler/received_packet_handler.go
index ed7fea72..7db808d7 100644
--- a/ackhandler/received_packet_handler.go
+++ b/ackhandler/received_packet_handler.go
@@ -67,7 +67,7 @@ func (h *receivedPacketHandler) getNackRanges() ([]frames.NackRange, EntropyAccu
 	var ranges []frames.NackRange
 	inRange := false
 	entropy := h.highestInOrderObservedEntropy
-	for i := h.highestInOrderObserved + 1; i <= h.largestObserved; i++ {
+	for i := h.largestObserved; i > h.highestInOrderObserved; i-- {
 		entropyBit, ok := h.packetHistory[i]
 		if !ok {
 			if !inRange {
@@ -78,7 +78,7 @@ func (h *receivedPacketHandler) getNackRanges() ([]frames.NackRange, EntropyAccu
 				ranges = append(ranges, r)
 				inRange = true
 			} else {
-				ranges[len(ranges)-1].LastPacketNumber++
+				ranges[len(ranges)-1].FirstPacketNumber--
 			}
 		} else {
 			inRange = false
diff --git a/ackhandler/received_packet_handler_test.go b/ackhandler/received_packet_handler_test.go
index f218ddad..bff0847c 100644
--- a/ackhandler/received_packet_handler_test.go
+++ b/ackhandler/received_packet_handler_test.go
@@ -117,8 +117,7 @@ var _ = Describe("receivedPacketHandler", func() {
 			Expect(handler.largestObserved).To(Equal(protocol.PacketNumber(9)))
 			nackRanges, entropy := handler.getNackRanges()
 			Expect(len(nackRanges)).To(Equal(1))
-			Expect(nackRanges[0].FirstPacketNumber).To(Equal(protocol.PacketNumber(5)))
-			Expect(nackRanges[0].LastPacketNumber).To(Equal(protocol.PacketNumber(5)))
+			Expect(nackRanges[0]).To(Equal(frames.NackRange{FirstPacketNumber: 5, LastPacketNumber: 5}))
 			Expect(handler.highestInOrderObserved).To(Equal(protocol.PacketNumber(4)))
 			Expect(entropy).To(Equal(expectedEntropy))
 		})
@@ -139,8 +138,7 @@ var _ = Describe("receivedPacketHandler", func() {
 			Expect(handler.largestObserved).To(Equal(protocol.PacketNumber(11)))
 			nackRanges, entropy := handler.getNackRanges()
 			Expect(len(nackRanges)).To(Equal(1))
-			Expect(nackRanges[0].FirstPacketNumber).To(Equal(protocol.PacketNumber(5)))
-			Expect(nackRanges[0].LastPacketNumber).To(Equal(protocol.PacketNumber(6)))
+			Expect(nackRanges[0]).To(Equal(frames.NackRange{FirstPacketNumber: 5, LastPacketNumber: 6}))
 			Expect(handler.highestInOrderObserved).To(Equal(protocol.PacketNumber(4)))
 			Expect(entropy).To(Equal(expectedEntropy))
 		})
@@ -161,10 +159,8 @@ var _ = Describe("receivedPacketHandler", func() {
 			Expect(handler.largestObserved).To(Equal(protocol.PacketNumber(9)))
 			nackRanges, entropy := handler.getNackRanges()
 			Expect(len(nackRanges)).To(Equal(2))
-			Expect(nackRanges[0].FirstPacketNumber).To(Equal(protocol.PacketNumber(3)))
-			Expect(nackRanges[0].LastPacketNumber).To(Equal(protocol.PacketNumber(3)))
-			Expect(nackRanges[1].FirstPacketNumber).To(Equal(protocol.PacketNumber(7)))
-			Expect(nackRanges[1].LastPacketNumber).To(Equal(protocol.PacketNumber(7)))
+			Expect(nackRanges[0]).To(Equal(frames.NackRange{FirstPacketNumber: 7, LastPacketNumber: 7}))
+			Expect(nackRanges[1]).To(Equal(frames.NackRange{FirstPacketNumber: 3, LastPacketNumber: 3}))
 			Expect(handler.highestInOrderObserved).To(Equal(protocol.PacketNumber(2)))
 			Expect(entropy).To(Equal(expectedEntropy))
 		})
@@ -182,10 +178,8 @@ var _ = Describe("receivedPacketHandler", func() {
 			Expect(handler.largestObserved).To(Equal(protocol.PacketNumber(9)))
 			nackRanges, entropy := handler.getNackRanges()
 			Expect(len(nackRanges)).To(Equal(2))
-			Expect(nackRanges[0].FirstPacketNumber).To(Equal(protocol.PacketNumber(2)))
-			Expect(nackRanges[0].LastPacketNumber).To(Equal(protocol.PacketNumber(4)))
-			Expect(nackRanges[1].FirstPacketNumber).To(Equal(protocol.PacketNumber(7)))
-			Expect(nackRanges[1].LastPacketNumber).To(Equal(protocol.PacketNumber(8)))
+			Expect(nackRanges[0]).To(Equal(frames.NackRange{FirstPacketNumber: 7, LastPacketNumber: 8}))
+			Expect(nackRanges[1]).To(Equal(frames.NackRange{FirstPacketNumber: 2, LastPacketNumber: 4}))
 			Expect(handler.highestInOrderObserved).To(Equal(protocol.PacketNumber(1)))
 			Expect(entropy).To(Equal(expectedEntropy))
 		})