diff --git a/ipn/ipnlocal/local.go b/ipn/ipnlocal/local.go
index c4bb293ec..aed1f70fa 100644
--- a/ipn/ipnlocal/local.go
+++ b/ipn/ipnlocal/local.go
@@ -31,6 +31,7 @@
 	"sync/atomic"
 	"time"
 
+	"github.com/gaissmai/bart"
 	"go4.org/mem"
 	"go4.org/netipx"
 	"golang.org/x/net/dns/dnsmessage"
@@ -62,6 +63,7 @@
 	"tailscale.com/net/netns"
 	"tailscale.com/net/netutil"
 	"tailscale.com/net/packet"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/net/traffic"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/net/tsdial"
@@ -2510,6 +2512,7 @@ func (b *LocalBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 	for k := range changedAllowedIPs {
 		b.e.SyncDevicePeer(k)
 	}
+	b.setDataPlanePeerRoutes()
 
 	// Reset the WireGuard session for peers whose disco key changed in
 	// a way that indicates a restart, flushing their dead session keys;
@@ -2524,11 +2527,9 @@ func (b *LocalBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
 	// and its lazy peer creation reads live state via
 	// [wgengine.Engine.SetPeerConfigFunc]. What still rides
 	// authReconfig is everything else derived from the full peer set:
-	// OS routes (router.Config), the quad-100 resolver's MagicDNS
-	// hosts map (dnsConfigForNetmap), and tstun's per-peer config
-	// (masquerade addresses and jailed peers, via SetWGConfig). Once
-	// those become delta-aware too, this can be gated on the route
-	// manager's OS-routes changes and the tstun-relevant fields
+	// OS routes (router.Config) and the quad-100 resolver's MagicDNS
+	// hosts map (dnsConfigForNetmap). Once those become delta-aware
+	// too, this can be gated on the route manager's OS-routes changes
 	// instead of firing on every peer change.
 	needsAuthReconfig = needsAuthReconfig || peersUpsertedOrRemoved
 	if needsAuthReconfig {
@@ -6177,6 +6178,10 @@ func (b *LocalBackend) authReconfigLocked() {
 			cfg.Peers[i].AllowedIPs = extras.AppendTo(cfg.Peers[i].AllowedIPs)
 		}
 	}
+	// The prefs and extras commits above can both change the outbound
+	// table (such as installing the selected exit node's /0 routes),
+	// so refresh the data plane's view of it.
+	b.setDataPlanePeerRoutes()
 
 	err = b.e.Reconfig(cfg, rcfg, dcfg)
 	if err == wgengine.ErrNoChanges {
@@ -6190,6 +6195,37 @@ func (b *LocalBackend) authReconfigLocked() {
 	}
 }
 
+// setDataPlanePeerRoutes pushes the route manager's outbound table and
+// this node's native Tailscale addresses into the engine's tun-layer
+// data plane, which uses them for per-packet NAT rewrites and
+// jailed-filter selection. It must be called after every route manager
+// commit that can change the outbound table or the set of peers with
+// data-plane attributes: netmap updates (full or delta), prefs changes,
+// and extra-allowed-IP changes.
+//
+// When no current peer is jailed or masqueraded, it installs nil, which
+// keeps the data plane's per-packet fast path to a nil check.
+func (b *LocalBackend) setDataPlanePeerRoutes() {
+	nb := b.currentNode()
+	var native4, native6 netip.Addr
+	var routes *bart.Table[*routemanager.PeerRoute]
+	if nb.routeMgr.HasDataPlaneAttrs() {
+		routes = nb.routeMgr.Outbound()
+		if nm := nb.NetMap(); nm != nil {
+			for _, pfx := range nm.GetAddresses().All() {
+				a := pfx.Addr()
+				switch {
+				case a.Is4() && !native4.IsValid() && tsaddr.IsTailscaleIP(a):
+					native4 = a
+				case a.Is6() && !native6.IsValid() && tsaddr.IsTailscaleIP(a):
+					native6 = a
+				}
+			}
+		}
+	}
+	b.e.SetPeerRoutes(native4, native6, routes)
+}
+
 // shouldUseOneCGNATRoute reports whether we should prefer to make one big
 // CGNAT /10 route rather than a /32 per peer.
 //
@@ -7306,6 +7342,7 @@ func (b *LocalBackend) setNetMapLocked(nm *netmap.NetworkMap) {
 		login = cmp.Or(profileFromView(nm.UserProfiles[nm.User()]).LoginName, "<missing-profile>")
 	}
 	discoChanged := b.currentNode().SetNetMap(nm)
+	b.setDataPlanePeerRoutes()
 	if ms, ok := b.sys.MagicSock.GetOK(); ok {
 		if nm != nil {
 			if nm.Cached {
diff --git a/ipn/ipnlocal/state_test.go b/ipn/ipnlocal/state_test.go
index 47cf595ed..d96ebb959 100644
--- a/ipn/ipnlocal/state_test.go
+++ b/ipn/ipnlocal/state_test.go
@@ -17,6 +17,7 @@
 	"time"
 
 	qt "github.com/frankban/quicktest"
+	"github.com/gaissmai/bart"
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 
@@ -29,6 +30,7 @@
 	"tailscale.com/net/dns"
 	"tailscale.com/net/netmon"
 	"tailscale.com/net/packet"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/net/tsdial"
 	"tailscale.com/tailcfg"
 	"tailscale.com/tsd"
@@ -1973,6 +1975,9 @@ func (e *mockEngine) SetJailedFilter(f *filter.Filter) {
 	e.mu.Unlock()
 }
 
+func (e *mockEngine) SetPeerRoutes(native4, native6 netip.Addr, routes *bart.Table[*routemanager.PeerRoute]) {
+}
+
 func (e *mockEngine) SetStatusCallback(cb wgengine.StatusCallback) {
 	e.mu.Lock()
 	e.statusCb = cb
diff --git a/net/tstun/wrap.go b/net/tstun/wrap.go
index dbaabdc0b..7107fa592 100644
--- a/net/tstun/wrap.go
+++ b/net/tstun/wrap.go
@@ -9,9 +9,7 @@
 	"io"
 	"net/netip"
 	"os"
-	"reflect"
 	"runtime"
-	"slices"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -28,6 +26,7 @@
 	"tailscale.com/feature/buildfeatures"
 	"tailscale.com/net/packet"
 	"tailscale.com/net/packet/checksum"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/syncs"
 	"tailscale.com/tstime/mono"
@@ -587,9 +586,9 @@ func findV6(addrs []netip.Prefix) netip.Addr {
 	return netip.Addr{}
 }
 
-// peerConfigTable contains configuration for individual peers and related
-// information necessary to perform peer-specific operations.  It should be
-// treated as immutable.
+// peerConfigTable contains the per-peer route attributes and related
+// information necessary to perform peer-specific operations. It should
+// be treated as immutable.
 //
 // The nil value is a valid configuration.
 type peerConfigTable struct {
@@ -602,57 +601,17 @@ type peerConfigTable struct {
 	// inbound packet is IPv6.
 	nativeAddr4, nativeAddr6 netip.Addr
 
-	// byIP contains configuration for each peer, indexed by a peer's IP
-	// address(es).
-	byIP bart.Table[*peerConfig]
-
-	// masqAddrCounts is a count of peers by MasqueradeAsIP.
-	// TODO? for logging
-	masqAddrCounts map[netip.Addr]int
-}
-
-// peerConfig is the configuration for a single peer.
-type peerConfig struct {
-	// dstMasqAddr{4,6} are the addresses that should be used as the
-	// source address when masquerading packets to this peer (i.e.
-	// SNAT). If an address is not valid, the packet should not be
-	// masqueraded for that address family.
-	dstMasqAddr4 netip.Addr
-	dstMasqAddr6 netip.Addr
-
-	// jailed is whether this peer is "jailed" (i.e. is restricted from being
-	// able to initiate connections to this node). This is the case for shared
-	// nodes.
-	jailed bool
+	// byIP maps a peer's IP addresses and routed prefixes to the
+	// peer's route attributes. It is a shared immutable snapshot
+	// from [routemanager.RouteManager.Outbound].
+	byIP *bart.Table[*routemanager.PeerRoute]
 }
 
 func (c *peerConfigTable) String() string {
 	if c == nil {
 		return "peerConfigTable(nil)"
 	}
-	var b strings.Builder
-	b.WriteString("peerConfigTable{")
-	fmt.Fprintf(&b, "nativeAddr4: %v, ", c.nativeAddr4)
-	fmt.Fprintf(&b, "nativeAddr6: %v, ", c.nativeAddr6)
-
-	// TODO: figure out how to iterate/debug/print c.byIP
-
-	b.WriteString("}")
-
-	return b.String()
-}
-
-func (c *peerConfig) String() string {
-	if c == nil {
-		return "peerConfig(nil)"
-	}
-	var b strings.Builder
-	b.WriteString("peerConfig{")
-	fmt.Fprintf(&b, "dstMasqAddr4: %v, ", c.dstMasqAddr4)
-	fmt.Fprintf(&b, "dstMasqAddr6: %v, ", c.dstMasqAddr6)
-	fmt.Fprintf(&b, "jailed: %v}", c.jailed)
-
-	return b.String()
+	return fmt.Sprintf("peerConfigTable{nativeAddr4: %v, nativeAddr6: %v}", c.nativeAddr4, c.nativeAddr6)
 }
 
 // mapDstIP returns the destination IP to use for a packet to dst.
@@ -675,10 +634,10 @@ func (pc *peerConfigTable) mapDstIP(src, oldDst netip.Addr) netip.Addr {
 		return oldDst
 	}
 
-	if oldDst.Is4() && pc.nativeAddr4.IsValid() && c.dstMasqAddr4 == oldDst {
+	if oldDst.Is4() && pc.nativeAddr4.IsValid() && c.MasqAddr4 == oldDst {
 		return pc.nativeAddr4
 	}
-	if oldDst.Is6() && pc.nativeAddr6.IsValid() && c.dstMasqAddr6 == oldDst {
+	if oldDst.Is6() && pc.nativeAddr6.IsValid() && c.MasqAddr6 == oldDst {
 		return pc.nativeAddr6
 	}
 	return oldDst
@@ -708,105 +667,17 @@ func (pc *peerConfigTable) selectSrcIP(oldSrc, dst netip.Addr) netip.Addr {
 
 	// Perform SNAT based on the address family and whether we have a valid
 	// addr.
-	if oldSrc.Is4() && c.dstMasqAddr4.IsValid() {
-		return c.dstMasqAddr4
+	if oldSrc.Is4() && c.MasqAddr4.IsValid() {
+		return c.MasqAddr4
 	}
-	if oldSrc.Is6() && c.dstMasqAddr6.IsValid() {
-		return c.dstMasqAddr6
+	if oldSrc.Is6() && c.MasqAddr6.IsValid() {
+		return c.MasqAddr6
 	}
 
 	// No SNAT; use old src
 	return oldSrc
 }
 
-// peerConfigTableFromWGConfig generates a peerConfigTable from nm. If NAT is
-// not required, and no additional configuration is present, it returns nil.
-func peerConfigTableFromWGConfig(wcfg *wgcfg.Config) *peerConfigTable {
-	if wcfg == nil {
-		return nil
-	}
-
-	nativeAddr4 := findV4(wcfg.Addresses)
-	nativeAddr6 := findV6(wcfg.Addresses)
-	if !nativeAddr4.IsValid() && !nativeAddr6.IsValid() {
-		return nil
-	}
-
-	ret := &peerConfigTable{
-		nativeAddr4:    nativeAddr4,
-		nativeAddr6:    nativeAddr6,
-		masqAddrCounts: make(map[netip.Addr]int),
-	}
-
-	// When using an exit node that requires masquerading, we need to
-	// fill out the routing table with all peers not just the ones that
-	// require masquerading.
-	exitNodeRequiresMasq := false // true if using an exit node and it requires masquerading
-	for _, p := range wcfg.Peers {
-		isExitNode := slices.Contains(p.AllowedIPs, tsaddr.AllIPv4()) || slices.Contains(p.AllowedIPs, tsaddr.AllIPv6())
-		if isExitNode {
-			hasMasqAddr := false ||
-				(p.V4MasqAddr != nil && p.V4MasqAddr.IsValid()) ||
-				(p.V6MasqAddr != nil && p.V6MasqAddr.IsValid())
-			if hasMasqAddr {
-				exitNodeRequiresMasq = true
-			}
-			break
-		}
-	}
-
-	byIPSize := 0
-	for i := range wcfg.Peers {
-		p := &wcfg.Peers[i]
-
-		// Build a routing table that configures DNAT (i.e. changing
-		// the V4MasqAddr/V6MasqAddr for a given peer to the current
-		// peer's v4/v6 IP).
-		var addrToUse4, addrToUse6 netip.Addr
-		if p.V4MasqAddr != nil && p.V4MasqAddr.IsValid() {
-			addrToUse4 = *p.V4MasqAddr
-			ret.masqAddrCounts[addrToUse4]++
-		}
-		if p.V6MasqAddr != nil && p.V6MasqAddr.IsValid() {
-			addrToUse6 = *p.V6MasqAddr
-			ret.masqAddrCounts[addrToUse6]++
-		}
-
-		// If the exit node requires masquerading, set the masquerade
-		// addresses to our native addresses.
-		if exitNodeRequiresMasq {
-			if !addrToUse4.IsValid() && nativeAddr4.IsValid() {
-				addrToUse4 = nativeAddr4
-			}
-			if !addrToUse6.IsValid() && nativeAddr6.IsValid() {
-				addrToUse6 = nativeAddr6
-			}
-		}
-
-		if !addrToUse4.IsValid() && !addrToUse6.IsValid() && !p.IsJailed {
-			// NAT not required for this peer.
-			continue
-		}
-
-		// Use the same peer configuration for each address of the peer.
-		pc := &peerConfig{
-			dstMasqAddr4: addrToUse4,
-			dstMasqAddr6: addrToUse6,
-			jailed:       p.IsJailed,
-		}
-
-		// Insert an entry into our routing table for each allowed IP.
-		for _, ip := range p.AllowedIPs {
-			ret.byIP.Insert(ip, pc)
-			byIPSize++
-		}
-	}
-	if byIPSize == 0 && len(ret.masqAddrCounts) == 0 {
-		return nil
-	}
-	return ret
-}
-
 func (pc *peerConfigTable) inboundPacketIsJailed(p *packet.Parsed) bool {
 	if pc == nil {
 		return false
@@ -815,7 +686,7 @@ func (pc *peerConfigTable) inboundPacketIsJailed(p *packet.Parsed) bool {
 	if !ok {
 		return false
 	}
-	return c.jailed
+	return c.Jailed
 }
 
 func (pc *peerConfigTable) outboundPacketIsJailed(p *packet.Parsed) bool {
@@ -826,7 +697,7 @@ func (pc *peerConfigTable) outboundPacketIsJailed(p *packet.Parsed) bool {
 	if !ok {
 		return false
 	}
-	return c.jailed
+	return c.Jailed
 }
 
 // SetIPer is the interface expected to be implemented by the TAP implementation
@@ -836,16 +707,40 @@ type SetIPer interface {
 	SetIP(ipV4, ipV6 netip.Addr) error
 }
 
-// SetWGConfig is called when a new NetworkMap is received.
+// SetWGConfig is called when a new NetworkMap is received. Its only
+// remaining job is updating the TAP device's IP addresses; the
+// per-peer route attributes arrive via [Wrapper.SetPeerRoutes].
 func (t *Wrapper) SetWGConfig(wcfg *wgcfg.Config) {
 	if t.isTAP {
 		if sip, ok := t.tdev.(SetIPer); ok {
 			sip.SetIP(findV4(wcfg.Addresses), findV6(wcfg.Addresses))
 		}
 	}
-	cfg := peerConfigTableFromWGConfig(wcfg)
+}
+
+// SetPeerRoutes is called whenever this node's Tailscale addresses or
+// the route manager's outbound table change. native4 and native6 are
+// this node's own Tailscale addresses, and routes maps each peer's
+// addresses and routed prefixes to its route attributes.
+//
+// A nil routes table disables all per-packet peer processing (NAT
+// rewrites and jailed-filter selection); callers pass nil when no
+// current peer has any such attributes, which keeps the common
+// per-packet path to a nil check.
+func (t *Wrapper) SetPeerRoutes(native4, native6 netip.Addr, routes *bart.Table[*routemanager.PeerRoute]) {
+	var cfg *peerConfigTable
+	if routes != nil && (native4.IsValid() || native6.IsValid()) {
+		cfg = &peerConfigTable{
+			nativeAddr4: native4,
+			nativeAddr6: native6,
+			byIP:        routes,
+		}
+	}
 	old := t.peerConfig.Swap(cfg)
-	if !reflect.DeepEqual(old, cfg) {
+	// Log only on nil-ness or native address transitions; the routes
+	// table changes with every routing update and is too chatty to log.
+	if (old == nil) != (cfg == nil) ||
+		(old != nil && (old.nativeAddr4 != cfg.nativeAddr4 || old.nativeAddr6 != cfg.nativeAddr6)) {
 		t.logf("peer config: %v", cfg)
 	}
 }
diff --git a/net/tstun/wrap_test.go b/net/tstun/wrap_test.go
index 631dc083e..7fd4f2ce9 100644
--- a/net/tstun/wrap_test.go
+++ b/net/tstun/wrap_test.go
@@ -18,6 +18,7 @@
 	"unicode"
 	"unsafe"
 
+	"github.com/gaissmai/bart"
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/tailscale/wireguard-go/tun/tuntest"
@@ -29,6 +30,7 @@
 	"tailscale.com/net/netaddr"
 	"tailscale.com/net/packet"
 	"tailscale.com/net/packet/checksum"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/tstest"
 	"tailscale.com/tstime/mono"
 	"tailscale.com/types/ipproto"
@@ -42,7 +44,6 @@
 	"tailscale.com/util/usermetric"
 	"tailscale.com/wgengine/filter"
 	"tailscale.com/wgengine/netstack/gro"
-	"tailscale.com/wgengine/wgcfg"
 )
 
 func udp4(src, dst string, sport, dport uint16) []byte {
@@ -710,22 +711,23 @@ func TestFilterDiscoLoop(t *testing.T) {
 }
 
 // TODO(andrew-d): refactor this test to no longer use addrFam, after #11945
-// removed it in peerConfigFromWGConfig
 func TestPeerCfg_NAT(t *testing.T) {
-	node := func(ip, masqIP netip.Addr, otherAllowedIPs ...netip.Prefix) wgcfg.Peer {
-		p := wgcfg.Peer{
-			PublicKey: key.NewNode().Public(),
-			AllowedIPs: []netip.Prefix{
-				netip.PrefixFrom(ip, ip.BitLen()),
-			},
+	type testPeer struct {
+		pr   *routemanager.PeerRoute
+		pfxs []netip.Prefix
+	}
+	node := func(ip, masqIP netip.Addr, otherAllowedIPs ...netip.Prefix) testPeer {
+		pr := &routemanager.PeerRoute{Key: key.NewNode().Public()}
+		switch {
+		case masqIP.Is4():
+			pr.MasqAddr4 = masqIP
+		case masqIP.Is6():
+			pr.MasqAddr6 = masqIP
 		}
-		if masqIP.Is4() {
-			p.V4MasqAddr = new(masqIP)
-		} else {
-			p.V6MasqAddr = new(masqIP)
+		return testPeer{
+			pr:   pr,
+			pfxs: append([]netip.Prefix{netip.PrefixFrom(ip, ip.BitLen())}, otherAllowedIPs...),
 		}
-		p.AllowedIPs = append(p.AllowedIPs, otherAllowedIPs...)
-		return p
 	}
 	test := func(addrFam ipproto.Version) {
 		var (
@@ -734,7 +736,6 @@ func TestPeerCfg_NAT(t *testing.T) {
 			selfNativeIP = netip.MustParseAddr("100.64.0.1")
 			selfEIP1     = netip.MustParseAddr("100.64.1.1")
 			selfEIP2     = netip.MustParseAddr("100.64.1.2")
-			selfAddrs    = []netip.Prefix{netip.PrefixFrom(selfNativeIP, selfNativeIP.BitLen())}
 
 			peer1IP = netip.MustParseAddr("100.64.0.2")
 			peer2IP = netip.MustParseAddr("100.64.0.3")
@@ -749,7 +750,6 @@ func TestPeerCfg_NAT(t *testing.T) {
 			selfNativeIP = netip.MustParseAddr("fd7a:115c:a1e0::a")
 			selfEIP1 = netip.MustParseAddr("fd7a:115c:a1e0::1a")
 			selfEIP2 = netip.MustParseAddr("fd7a:115c:a1e0::1b")
-			selfAddrs = []netip.Prefix{netip.PrefixFrom(selfNativeIP, selfNativeIP.BitLen())}
 
 			peer1IP = netip.MustParseAddr("fd7a:115c:a1e0::b")
 			peer2IP = netip.MustParseAddr("fd7a:115c:a1e0::c")
@@ -769,13 +769,13 @@ type dnatTest struct {
 
 		tests := []struct {
 			name    string
-			wcfg    *wgcfg.Config
+			peers   []testPeer                // nil means no config at all
 			snatMap map[netip.Addr]netip.Addr // dst -> src
 			dnat    []dnatTest
 		}{
 			{
-				name: "no-cfg",
-				wcfg: nil,
+				name:  "no-cfg",
+				peers: nil,
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfNativeIP,
 					peer2IP:  selfNativeIP,
@@ -789,12 +789,9 @@ type dnatTest struct {
 			},
 			{
 				name: "single-peer-requires-nat",
-				wcfg: &wgcfg.Config{
-					Addresses: selfAddrs,
-					Peers: []wgcfg.Peer{
-						node(peer1IP, noIP),
-						node(peer2IP, selfEIP2),
-					},
+				peers: []testPeer{
+					node(peer1IP, noIP),
+					node(peer2IP, selfEIP2),
 				},
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfNativeIP,
@@ -810,12 +807,9 @@ type dnatTest struct {
 			},
 			{
 				name: "multiple-peers-require-nat",
-				wcfg: &wgcfg.Config{
-					Addresses: selfAddrs,
-					Peers: []wgcfg.Peer{
-						node(peer1IP, selfEIP1),
-						node(peer2IP, selfEIP2),
-					},
+				peers: []testPeer{
+					node(peer1IP, selfEIP1),
+					node(peer2IP, selfEIP2),
 				},
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfEIP1,
@@ -831,12 +825,9 @@ type dnatTest struct {
 			},
 			{
 				name: "multiple-peers-require-nat-with-subnet",
-				wcfg: &wgcfg.Config{
-					Addresses: selfAddrs,
-					Peers: []wgcfg.Peer{
-						node(peer1IP, selfEIP1),
-						node(peer2IP, selfEIP2, subnet),
-					},
+				peers: []testPeer{
+					node(peer1IP, selfEIP1),
+					node(peer2IP, selfEIP2, subnet),
 				},
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfEIP1,
@@ -852,12 +843,9 @@ type dnatTest struct {
 			},
 			{
 				name: "multiple-peers-require-nat-with-default-route",
-				wcfg: &wgcfg.Config{
-					Addresses: selfAddrs,
-					Peers: []wgcfg.Peer{
-						node(peer1IP, selfEIP1),
-						node(peer2IP, selfEIP2, exitRoute),
-					},
+				peers: []testPeer{
+					node(peer1IP, selfEIP1),
+					node(peer2IP, selfEIP2, exitRoute),
 				},
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfEIP1,
@@ -873,12 +861,9 @@ type dnatTest struct {
 			},
 			{
 				name: "no-nat",
-				wcfg: &wgcfg.Config{
-					Addresses: selfAddrs,
-					Peers: []wgcfg.Peer{
-						node(peer1IP, noIP),
-						node(peer2IP, noIP),
-					},
+				peers: []testPeer{
+					node(peer1IP, noIP),
+					node(peer2IP, noIP),
 				},
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfNativeIP,
@@ -894,12 +879,9 @@ type dnatTest struct {
 			},
 			{
 				name: "exit-node-require-nat-peer-doesnt",
-				wcfg: &wgcfg.Config{
-					Addresses: selfAddrs,
-					Peers: []wgcfg.Peer{
-						node(peer1IP, noIP),
-						node(peer2IP, selfEIP2, exitRoute),
-					},
+				peers: []testPeer{
+					node(peer1IP, noIP),
+					node(peer2IP, selfEIP2, exitRoute),
 				},
 				snatMap: map[netip.Addr]netip.Addr{
 					peer1IP:  selfNativeIP,
@@ -916,7 +898,20 @@ type dnatTest struct {
 
 		for _, tc := range tests {
 			t.Run(fmt.Sprintf("%v/%v", addrFam, tc.name), func(t *testing.T) {
-				pcfg := peerConfigTableFromWGConfig(tc.wcfg)
+				var pcfg *peerConfigTable
+				if tc.peers != nil {
+					pcfg = &peerConfigTable{byIP: &bart.Table[*routemanager.PeerRoute]{}}
+					if selfNativeIP.Is4() {
+						pcfg.nativeAddr4 = selfNativeIP
+					} else {
+						pcfg.nativeAddr6 = selfNativeIP
+					}
+					for _, p := range tc.peers {
+						for _, pfx := range p.pfxs {
+							pcfg.byIP.Insert(pfx, p.pr)
+						}
+					}
+				}
 				for peer, want := range tc.snatMap {
 					if got := pcfg.selectSrcIP(selfNativeIP, peer); got != want {
 						t.Errorf("selectSrcIP[%v]: got %v; want %v", peer, got, want)
diff --git a/wgengine/magicsock/magicsock_test.go b/wgengine/magicsock/magicsock_test.go
index 69d64b43f..c6b187c68 100644
--- a/wgengine/magicsock/magicsock_test.go
+++ b/wgengine/magicsock/magicsock_test.go
@@ -33,6 +33,7 @@
 	"unsafe"
 
 	qt "github.com/frankban/quicktest"
+	"github.com/gaissmai/bart"
 	"github.com/google/go-cmp/cmp"
 	wgconn "github.com/tailscale/wireguard-go/conn"
 	"github.com/tailscale/wireguard-go/device"
@@ -54,6 +55,7 @@
 	"tailscale.com/net/netmon"
 	"tailscale.com/net/packet"
 	"tailscale.com/net/ping"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/net/stun"
 	"tailscale.com/net/stun/stuntest"
 	"tailscale.com/net/tstun"
@@ -247,6 +249,35 @@ func newMagicStackWithKey(t testing.TB, logf logger.Logf, ln nettype.PacketListe
 func (s *magicStack) Reconfig(cfg *wgcfg.Config) error {
 	s.tsTun.SetWGConfig(cfg)
 
+	// In production, LocalBackend feeds the tun-layer data plane its
+	// per-peer route attributes from the route manager. Tests that
+	// bypass LocalBackend need to build the table from cfg.Peers here
+	// so that masquerade rewrites and jailed classification work.
+	tbl := &bart.Table[*routemanager.PeerRoute]{}
+	for _, p := range cfg.Peers {
+		pr := &routemanager.PeerRoute{Key: p.PublicKey, Jailed: p.IsJailed}
+		if p.V4MasqAddr != nil && p.V4MasqAddr.IsValid() {
+			pr.MasqAddr4 = *p.V4MasqAddr
+		}
+		if p.V6MasqAddr != nil && p.V6MasqAddr.IsValid() {
+			pr.MasqAddr6 = *p.V6MasqAddr
+		}
+		for _, pfx := range p.AllowedIPs {
+			tbl.Insert(pfx, pr)
+		}
+	}
+	var native4, native6 netip.Addr
+	for _, pfx := range cfg.Addresses {
+		a := pfx.Addr()
+		switch {
+		case a.Is4() && !native4.IsValid():
+			native4 = a
+		case a.Is6() && !native6.IsValid():
+			native6 = a
+		}
+	}
+	s.tsTun.SetPeerRoutes(native4, native6, tbl)
+
 	// In production, LocalBackend installs a PeerByIPPacketFunc via
 	// Engine.SetPeerByIPPacketFunc. Tests that bypass LocalBackend need
 	// to install one here for outbound packet routing.
diff --git a/wgengine/userspace.go b/wgengine/userspace.go
index c9b66f07d..6e96caefb 100644
--- a/wgengine/userspace.go
+++ b/wgengine/userspace.go
@@ -18,6 +18,7 @@
 	"sync/atomic"
 	"time"
 
+	"github.com/gaissmai/bart"
 	"github.com/tailscale/wireguard-go/device"
 	"github.com/tailscale/wireguard-go/tun"
 	"go4.org/mem"
@@ -33,6 +34,7 @@
 	"tailscale.com/net/ipset"
 	"tailscale.com/net/netmon"
 	"tailscale.com/net/packet"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/net/sockstats"
 	"tailscale.com/net/tsdial"
 	"tailscale.com/net/tstun"
@@ -1023,6 +1025,10 @@ func (e *userspaceEngine) SetJailedFilter(filt *filter.Filter) {
 	e.tundev.SetJailedFilter(filt)
 }
 
+func (e *userspaceEngine) SetPeerRoutes(native4, native6 netip.Addr, routes *bart.Table[*routemanager.PeerRoute]) {
+	e.tundev.SetPeerRoutes(native4, native6, routes)
+}
+
 func (e *userspaceEngine) SetStatusCallback(cb StatusCallback) {
 	e.mu.Lock()
 	defer e.mu.Unlock()
diff --git a/wgengine/wgengine.go b/wgengine/wgengine.go
index 774e1c1aa..652774756 100644
--- a/wgengine/wgengine.go
+++ b/wgengine/wgengine.go
@@ -9,9 +9,11 @@
 	"net/netip"
 	"time"
 
+	"github.com/gaissmai/bart"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/net/dns"
 	"tailscale.com/net/packet"
+	"tailscale.com/net/routemanager"
 	"tailscale.com/tailcfg"
 	"tailscale.com/types/key"
 	"tailscale.com/types/netmap"
@@ -125,6 +127,17 @@ type Engine interface {
 	// SetJailedFilter updates the packet filter for jailed nodes.
 	SetJailedFilter(*filter.Filter)
 
+	// SetPeerRoutes updates the per-peer route attributes used by the
+	// tun-layer data plane for per-packet NAT rewrites and
+	// jailed-filter selection. native4 and native6 are this node's own
+	// Tailscale addresses, and routes maps each peer's addresses and
+	// routed prefixes to its attributes; it is a shared immutable
+	// snapshot from [routemanager.RouteManager.Outbound].
+	//
+	// A nil routes table disables all per-packet peer processing;
+	// callers pass nil when no current peer has any such attributes.
+	SetPeerRoutes(native4, native6 netip.Addr, routes *bart.Table[*routemanager.PeerRoute])
+
 	// SetStatusCallback sets the function to call when the
 	// WireGuard status changes.
 	SetStatusCallback(StatusCallback)