diff --git a/pkg/tcpip/stack/route.go b/pkg/tcpip/stack/route.go
index d51a2ebac..e571e8a1f 100644
--- a/pkg/tcpip/stack/route.go
+++ b/pkg/tcpip/stack/route.go
@@ -54,6 +54,11 @@ type Route struct {
 	// neighbor cache.
 	// +checklocks:mu
 	neighborEntry *neighborEntry
+
+	// mtu is the maximum transmission unit to use for this route.
+	// If mtu is 0, this field is ignored and the MTU of the outgoing NIC
+	// is used for egress packets.
+	mtu uint32
 }
 
 // +stateify savable
@@ -140,7 +145,7 @@ func (r *Route) fieldsLocked() RouteInfo {
 // ownership of the provided local address.
 //
 // Returns an empty route if validation fails.
-func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndpoint AssignableAddressEndpoint, localAddressNIC, outgoingNIC *nic, gateway, localAddr, remoteAddr tcpip.Address, handleLocal, multicastLoop bool) *Route {
+func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndpoint AssignableAddressEndpoint, localAddressNIC, outgoingNIC *nic, gateway, localAddr, remoteAddr tcpip.Address, handleLocal, multicastLoop bool, mtu uint32) *Route {
 	if localAddr.BitLen() == 0 {
 		localAddr = addressEndpoint.AddressWithPrefix().Address
 	}
@@ -165,6 +170,7 @@ func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndp
 		addressEndpoint,
 		handleLocal,
 		multicastLoop,
+		mtu,
 	)
 
 	return r
@@ -172,7 +178,7 @@ func constructAndValidateRoute(netProto tcpip.NetworkProtocolNumber, addressEndp
 
 // makeRoute initializes a new route. It takes ownership of the provided
 // AssignableAddressEndpoint.
-func makeRoute(netProto tcpip.NetworkProtocolNumber, gateway, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *nic, localAddressEndpoint AssignableAddressEndpoint, handleLocal, multicastLoop bool) *Route {
+func makeRoute(netProto tcpip.NetworkProtocolNumber, gateway, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *nic, localAddressEndpoint AssignableAddressEndpoint, handleLocal, multicastLoop bool, mtu uint32) *Route {
 	if localAddressNIC.stack != outgoingNIC.stack {
 		panic(fmt.Sprintf("cannot create a route with NICs from different stacks"))
 	}
@@ -198,7 +204,7 @@ func makeRoute(netProto tcpip.NetworkProtocolNumber, gateway, localAddr, remoteA
 		}
 	}
 
-	r := makeRouteInner(netProto, localAddr, remoteAddr, outgoingNIC, localAddressNIC, localAddressEndpoint, loop)
+	r := makeRouteInner(netProto, localAddr, remoteAddr, outgoingNIC, localAddressNIC, localAddressEndpoint, loop, mtu)
 	if r.Loop()&PacketOut == 0 {
 		// Packet will not leave the stack, no need for a gateway or a remote link
 		// address.
@@ -238,7 +244,7 @@ func makeRoute(netProto tcpip.NetworkProtocolNumber, gateway, localAddr, remoteA
 	return r
 }
 
-func makeRouteInner(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *nic, localAddressEndpoint AssignableAddressEndpoint, loop PacketLooping) *Route {
+func makeRouteInner(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr tcpip.Address, outgoingNIC, localAddressNIC *nic, localAddressEndpoint AssignableAddressEndpoint, loop PacketLooping, mtu uint32) *Route {
 	r := &Route{
 		routeInfo: routeInfo{
 			NetProto:         netProto,
@@ -249,6 +255,7 @@ func makeRouteInner(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr
 		},
 		localAddressNIC: localAddressNIC,
 		outgoingNIC:     outgoingNIC,
+		mtu:             mtu,
 	}
 
 	r.mu.Lock()
@@ -270,7 +277,7 @@ func makeLocalRoute(netProto tcpip.NetworkProtocolNumber, localAddr, remoteAddr
 	if outgoingNIC.IsLoopback() {
 		loop = PacketOut
 	}
-	return makeRouteInner(netProto, localAddr, remoteAddr, outgoingNIC, localAddressNIC, localAddressEndpoint, loop)
+	return makeRouteInner(netProto, localAddr, remoteAddr, outgoingNIC, localAddressNIC, localAddressEndpoint, loop, 0 /* mtu */)
 }
 
 // RemoteLinkAddress returns the link-layer (MAC) address of the next hop in
@@ -515,8 +522,11 @@ func (r *Route) DefaultTTL() uint8 {
 	return r.outgoingNIC.getNetworkEndpoint(r.NetProto()).DefaultTTL()
 }
 
-// MTU returns the MTU of the underlying network endpoint.
+// MTU returns the MTU of the route if present, otherwise the MTU of the underlying network endpoint.
 func (r *Route) MTU() uint32 {
+	if r.mtu > 0 {
+		return r.mtu
+	}
 	return r.outgoingNIC.getNetworkEndpoint(r.NetProto()).MTU()
 }
 
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 3c9b6d061..938a122ac 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -1192,7 +1192,7 @@ func (s *Stack) NewRouteForMulticast(nicID tcpip.NICID, remoteAddr tcpip.Address
 	}
 
 	if addressEndpoint := s.getAddressEP(nic, tcpip.Address{} /* localAddr */, remoteAddr, tcpip.Address{} /* srcHint */, netProto); addressEndpoint != nil {
-		return constructAndValidateRoute(netProto, addressEndpoint, nic, nic, tcpip.Address{} /* gateway */, tcpip.Address{} /* localAddr */, remoteAddr, s.handleLocal, false /* multicastLoop */)
+		return constructAndValidateRoute(netProto, addressEndpoint, nic, nic, tcpip.Address{} /* gateway */, tcpip.Address{} /* localAddr */, remoteAddr, s.handleLocal, false /* multicastLoop */, 0 /* mtu */)
 	}
 	return nil
 }
@@ -1303,14 +1303,14 @@ func isNICForwarding(nic *nic, proto tcpip.NetworkProtocolNumber) bool {
 // endpoint.
 //
 // +checklocksread:s.mu
-func (s *Stack) findRouteWithLocalAddrFromAnyInterfaceRLocked(outgoingNIC *nic, localAddr, remoteAddr, srcHint, gateway tcpip.Address, netProto tcpip.NetworkProtocolNumber, multicastLoop bool) *Route {
+func (s *Stack) findRouteWithLocalAddrFromAnyInterfaceRLocked(outgoingNIC *nic, localAddr, remoteAddr, srcHint, gateway tcpip.Address, netProto tcpip.NetworkProtocolNumber, multicastLoop bool, mtu uint32) *Route {
 	for _, aNIC := range s.nics {
 		addressEndpoint := s.getAddressEP(aNIC, localAddr, remoteAddr, srcHint, netProto)
 		if addressEndpoint == nil {
 			continue
 		}
 
-		if r := constructAndValidateRoute(netProto, addressEndpoint, aNIC /* localAddressNIC */, outgoingNIC, gateway, localAddr, remoteAddr, s.handleLocal, multicastLoop); r != nil {
+		if r := constructAndValidateRoute(netProto, addressEndpoint, aNIC /* localAddressNIC */, outgoingNIC, gateway, localAddr, remoteAddr, s.handleLocal, multicastLoop, mtu); r != nil {
 			return r
 		}
 	}
@@ -1359,11 +1359,12 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 					tcpip.Address{}, /* gateway */
 					localAddr,
 					remoteAddr,
-					nic, /* outboundNIC */
+					nic, /* outgoingNIC */
 					nic, /* localAddressNIC*/
 					addressEndpoint,
 					s.handleLocal,
 					multicastLoop,
+					0, /* mtu */
 				), nil
 			}
 		}
@@ -1398,7 +1399,7 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 					if needRoute {
 						gateway = route.Gateway
 					}
-					r := constructAndValidateRoute(netProto, addressEndpoint, nic /* outgoingNIC */, nic /* outgoingNIC */, gateway, localAddr, remoteAddr, s.handleLocal, multicastLoop)
+					r := constructAndValidateRoute(netProto, addressEndpoint, nic /* outgoingNIC */, nic /* outgoingNIC */, gateway, localAddr, remoteAddr, s.handleLocal, multicastLoop, route.MTU)
 					if r == nil {
 						panic(fmt.Sprintf("non-forwarding route validation failed with route table entry = %#v, id = %d, localAddr = %s, remoteAddr = %s", route, id, localAddr, remoteAddr))
 					}
@@ -1424,7 +1425,8 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 					chosenRoute = route
 					continue
 				}
-				if r := s.findRouteWithLocalAddrFromAnyInterfaceRLocked(nic, localAddr, remoteAddr, route.SourceHint, route.Gateway, netProto, multicastLoop); r != nil {
+
+				if r := s.findRouteWithLocalAddrFromAnyInterfaceRLocked(nic, localAddr, remoteAddr, route.SourceHint, route.Gateway, netProto, multicastLoop, route.MTU); r != nil {
 					return r
 				}
 			}
@@ -1453,7 +1455,7 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 		if id != 0 {
 			if aNIC, ok := s.nics[id]; ok {
 				if addressEndpoint := s.getAddressEP(aNIC, localAddr, remoteAddr, chosenRoute.SourceHint, netProto); addressEndpoint != nil {
-					if r := constructAndValidateRoute(netProto, addressEndpoint, aNIC /* localAddressNIC */, nic /* outgoingNIC */, gateway, localAddr, remoteAddr, s.handleLocal, multicastLoop); r != nil {
+					if r := constructAndValidateRoute(netProto, addressEndpoint, aNIC /* localAddressNIC */, nic /* outgoingNIC */, gateway, localAddr, remoteAddr, s.handleLocal, multicastLoop, chosenRoute.MTU); r != nil {
 						return r, nil
 					}
 				}
@@ -1466,7 +1468,7 @@ func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, n
 		if id == 0 {
 			// If an interface is not specified, try to find a NIC that holds the local
 			// address endpoint to construct a route.
-			if r := s.findRouteWithLocalAddrFromAnyInterfaceRLocked(nic, localAddr, remoteAddr, chosenRoute.SourceHint, gateway, netProto, multicastLoop); r != nil {
+			if r := s.findRouteWithLocalAddrFromAnyInterfaceRLocked(nic, localAddr, remoteAddr, chosenRoute.SourceHint, gateway, netProto, multicastLoop, chosenRoute.MTU); r != nil {
 				return r, nil
 			}
 		}
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index 5ca31b25f..cf0605d80 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -831,7 +831,7 @@ func TestNetworkSendMultiRoute(t *testing.T) {
 	testSendTo(t, s, "\x06\x00\x00\x00", ep2, nil)
 }
 
-func testRoute(t *testing.T, s *stack.Stack, nic tcpip.NICID, srcAddr, dstAddr, expectedSrcAddr tcpip.Address) {
+func testRoute(t *testing.T, s *stack.Stack, nic tcpip.NICID, srcAddr, dstAddr, expectedSrcAddr tcpip.Address, expectedRouteMTU int) {
 	r, err := s.FindRoute(nic, srcAddr, dstAddr, fakeNetNumber, false /* multicastLoop */)
 	if err != nil {
 		t.Fatal("FindRoute failed:", err)
@@ -846,6 +846,10 @@ func testRoute(t *testing.T, s *stack.Stack, nic tcpip.NICID, srcAddr, dstAddr,
 	if r.RemoteAddress() != dstAddr {
 		t.Fatalf("got Route.RemoteAddress() = %s, want = %s", dstAddr, r.RemoteAddress())
 	}
+
+	if int(r.MTU()) != expectedRouteMTU {
+		t.Fatalf("got Route.MTU() = %d, want = %d", r.MTU(), expectedRouteMTU)
+	}
 }
 
 func testNoRoute(t *testing.T, s *stack.Stack, nic tcpip.NICID, srcAddr, dstAddr tcpip.Address) {
@@ -1043,6 +1047,8 @@ func TestRouteWithDownNIC(t *testing.T) {
 	var addr2 = tcpip.AddrFrom4Slice([]byte("\x02\x00\x00\x00"))
 	var nic1Dst = tcpip.AddrFrom4Slice([]byte("\x05\x00\x00\x00"))
 	var nic2Dst = tcpip.AddrFrom4Slice([]byte("\x06\x00\x00\x00"))
+	var nic1RouteMTU = 1500
+	var nic2RouteMTU = 1460
 
 	setup := func(t *testing.T) (*stack.Stack, *channel.Endpoint, *channel.Endpoint) {
 		s := stack.New(stack.Options{
@@ -1094,8 +1100,8 @@ func TestRouteWithDownNIC(t *testing.T) {
 				t.Fatal(err)
 			}
 			s.SetRouteTable([]tcpip.Route{
-				{Destination: subnet1, Gateway: tcpip.AddrFrom4Slice([]byte("\x00\x00\x00\x00")), NIC: nicID1},
-				{Destination: subnet0, Gateway: tcpip.AddrFrom4Slice([]byte("\x00\x00\x00\x00")), NIC: nicID2},
+				{Destination: subnet1, Gateway: tcpip.AddrFrom4Slice([]byte("\x00\x00\x00\x00")), NIC: nicID1, MTU: uint32(nic1RouteMTU)},
+				{Destination: subnet0, Gateway: tcpip.AddrFrom4Slice([]byte("\x00\x00\x00\x00")), NIC: nicID2, MTU: uint32(nic2RouteMTU)},
 			})
 		}
 
@@ -1110,14 +1116,14 @@ func TestRouteWithDownNIC(t *testing.T) {
 				s, _, _ := setup(t)
 
 				// Test routes to odd address.
-				testRoute(t, s, unspecifiedNIC, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), addr1)
-				testRoute(t, s, unspecifiedNIC, addr1, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), addr1)
-				testRoute(t, s, nicID1, addr1, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), addr1)
+				testRoute(t, s, unspecifiedNIC, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), addr1, nic1RouteMTU)
+				testRoute(t, s, unspecifiedNIC, addr1, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), addr1, nic1RouteMTU)
+				testRoute(t, s, nicID1, addr1, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), addr1, nic1RouteMTU)
 
 				// Test routes to even address.
-				testRoute(t, s, unspecifiedNIC, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), addr2)
-				testRoute(t, s, unspecifiedNIC, addr2, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), addr2)
-				testRoute(t, s, nicID2, addr2, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), addr2)
+				testRoute(t, s, unspecifiedNIC, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), addr2, nic2RouteMTU)
+				testRoute(t, s, unspecifiedNIC, addr2, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), addr2, nic2RouteMTU)
+				testRoute(t, s, nicID2, addr2, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), addr2, nic2RouteMTU)
 
 				// Bringing NIC1 down should result in no routes to odd addresses. Routes to
 				// even addresses should continue to be available as NIC2 is still up.
@@ -1127,9 +1133,9 @@ func TestRouteWithDownNIC(t *testing.T) {
 				testNoRoute(t, s, unspecifiedNIC, tcpip.Address{}, nic1Dst)
 				testNoRoute(t, s, unspecifiedNIC, addr1, nic1Dst)
 				testNoRoute(t, s, nicID1, addr1, nic1Dst)
-				testRoute(t, s, unspecifiedNIC, tcpip.Address{}, nic2Dst, addr2)
-				testRoute(t, s, unspecifiedNIC, addr2, nic2Dst, addr2)
-				testRoute(t, s, nicID2, addr2, nic2Dst, addr2)
+				testRoute(t, s, unspecifiedNIC, tcpip.Address{}, nic2Dst, addr2, nic2RouteMTU)
+				testRoute(t, s, unspecifiedNIC, addr2, nic2Dst, addr2, nic2RouteMTU)
+				testRoute(t, s, nicID2, addr2, nic2Dst, addr2, nic2RouteMTU)
 
 				// Bringing NIC2 down should result in no routes to even addresses. No
 				// route should be available to any address as routes to odd addresses
@@ -1151,9 +1157,9 @@ func TestRouteWithDownNIC(t *testing.T) {
 					if err := upFn(s, nicID1); err != nil {
 						t.Fatalf("test.upFn(_, %d): %s", nicID1, err)
 					}
-					testRoute(t, s, unspecifiedNIC, tcpip.Address{}, nic1Dst, addr1)
-					testRoute(t, s, unspecifiedNIC, addr1, nic1Dst, addr1)
-					testRoute(t, s, nicID1, addr1, nic1Dst, addr1)
+					testRoute(t, s, unspecifiedNIC, tcpip.Address{}, nic1Dst, addr1, nic1RouteMTU)
+					testRoute(t, s, unspecifiedNIC, addr1, nic1Dst, addr1, nic1RouteMTU)
+					testRoute(t, s, nicID1, addr1, nic1Dst, addr1, nic1RouteMTU)
 					testNoRoute(t, s, unspecifiedNIC, tcpip.Address{}, nic2Dst)
 					testNoRoute(t, s, unspecifiedNIC, addr2, nic2Dst)
 					testNoRoute(t, s, nicID2, addr2, nic2Dst)
@@ -1286,6 +1292,8 @@ func TestRoutes(t *testing.T) {
 	// Set a route table that sends all packets with odd destination
 	// addresses through the first NIC, and all even destination address
 	// through the second one.
+	nic1RouteMTU := 1500
+	nic2RouteMTU := 1460
 	{
 		subnet0, err := tcpip.NewSubnet(tcpip.AddrFromSlice([]byte("\x00\x00\x00\x00")), tcpip.MaskFrom("\x01\x00\x00\x00"))
 		if err != nil {
@@ -1295,25 +1303,26 @@ func TestRoutes(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+
 		s.SetRouteTable([]tcpip.Route{
-			{Destination: subnet1, Gateway: tcpip.AddrFromSlice([]byte("\x00\x00\x00\x00")), NIC: 1},
-			{Destination: subnet0, Gateway: tcpip.AddrFromSlice([]byte("\x00\x00\x00\x00")), NIC: 2},
+			{Destination: subnet1, Gateway: tcpip.AddrFromSlice([]byte("\x00\x00\x00\x00")), NIC: 1, MTU: uint32(nic1RouteMTU)},
+			{Destination: subnet0, Gateway: tcpip.AddrFromSlice([]byte("\x00\x00\x00\x00")), NIC: 2, MTU: uint32(nic2RouteMTU)},
 		})
 	}
 
 	// Test routes to odd address.
-	testRoute(t, s, 0, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")))
-	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")))
-	testRoute(t, s, 1, tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")))
-	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")))
-	testRoute(t, s, 1, tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")))
+	testRoute(t, s, 0, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), nic1RouteMTU)
+	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), nic1RouteMTU)
+	testRoute(t, s, 1, tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x01\x00\x00\x00")), nic1RouteMTU)
+	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")), nic1RouteMTU)
+	testRoute(t, s, 1, tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x05\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x03\x00\x00\x00")), nic1RouteMTU)
 
 	// Test routes to even address.
-	testRoute(t, s, 0, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")))
-	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")))
-	testRoute(t, s, 2, tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")))
-	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")))
-	testRoute(t, s, 2, tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")))
+	testRoute(t, s, 0, tcpip.Address{}, tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), nic2RouteMTU)
+	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")), nic2RouteMTU)
+	testRoute(t, s, 2, tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x02\x00\x00\x00")), nic2RouteMTU)
+	testRoute(t, s, 0, tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), nic2RouteMTU)
+	testRoute(t, s, 2, tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x06\x00\x00\x00")), tcpip.AddrFromSlice([]byte("\x04\x00\x00\x00")), nic2RouteMTU)
 
 	// Try to send to odd numbered address from even numbered ones, then
 	// vice-versa.
diff --git a/pkg/tcpip/tcpip.go b/pkg/tcpip/tcpip.go
index ec111d8cf..de6e03d07 100644
--- a/pkg/tcpip/tcpip.go
+++ b/pkg/tcpip/tcpip.go
@@ -1525,6 +1525,11 @@ type Route struct {
 	// SourceHint indicates a preferred source address to use when NICs
 	// have multiple addresses.
 	SourceHint Address
+
+	// MTU is the maximum transmission unit to use for this route.
+	// If MTU is 0, this field is ignored and the MTU of the NIC for which this route
+	// is configured is used for egress packets.
+	MTU uint32
 }
 
 // String implements the fmt.Stringer interface.