diff --git a/internal/server/backend.go b/internal/server/backend.go
index b434798..95f4911 100644
--- a/internal/server/backend.go
+++ b/internal/server/backend.go
@@ -42,6 +42,7 @@ func (b *Backend) List(ctx context.Context, sel *proto.BackendSelector) (*proto.
 			Domain: bk.Domain,
 			Phi:    bk.Phi,
 			Host:   bk.Host,
+			Usable: bk.Usable,
 		})
 	}
 
diff --git a/lib/tun2/backend.go b/lib/tun2/backend.go
index c9804c6..37af1aa 100644
--- a/lib/tun2/backend.go
+++ b/lib/tun2/backend.go
@@ -8,4 +8,5 @@ type Backend struct {
 	Domain string
 	Phi    float32
 	Host   string
+	Usable bool
 }
diff --git a/lib/tun2/connection.go b/lib/tun2/connection.go
index c53eefb..01b3b60 100644
--- a/lib/tun2/connection.go
+++ b/lib/tun2/connection.go
@@ -24,9 +24,15 @@ type Connection struct {
 	controlStream *smux.Stream
 	user          string
 	domain        string
-	cancel        context.CancelFunc
+	cf            context.CancelFunc
 	detector      *failure.Detector
 	Auth          *Auth
+	usable        bool
+}
+
+func (c *Connection) cancel() {
+	c.cf()
+	c.usable = false
 }
 
 // F logs key->value pairs as an ln.Fer
@@ -63,6 +69,10 @@ func (c *Connection) Ping() error {
 
 // OpenStream creates a new stream (connection) to the backend server.
 func (c *Connection) OpenStream() (net.Conn, error) {
+	if !c.usable {
+		return nil, ErrNoSuchBackend
+	}
+
 	err := c.conn.SetDeadline(time.Now().Add(time.Second))
 	if err != nil {
 		ln.Error(err, c.F())
diff --git a/lib/tun2/server.go b/lib/tun2/server.go
index 6f6f284..7d3b04e 100644
--- a/lib/tun2/server.go
+++ b/lib/tun2/server.go
@@ -102,6 +102,7 @@ func (s *Server) getBackendsForMatcher(bm backendMatcher) []Backend {
 			Domain: c.domain,
 			Phi:    float32(c.detector.Phi(time.Now())),
 			Host:   c.conn.RemoteAddr().String(),
+			Usable: c.usable,
 		})
 	}
 
@@ -334,7 +335,7 @@ func (s *Server) HandleConn(c net.Conn, isKCP bool) {
 		session:  session,
 		user:     tokenUser,
 		domain:   auth.Domain,
-		cancel:   cancel,
+		cf:       cancel,
 		detector: failure.New(15, 1),
 		Auth:     auth,
 	}
@@ -362,6 +363,7 @@ func (s *Server) HandleConn(c net.Conn, isKCP bool) {
 	conns = append(conns, connection)
 
 	s.domains.Set(auth.Domain, conns)
+	connection.usable = true
 
 	ticker := time.NewTicker(5 * time.Second)
 	defer ticker.Stop()
@@ -371,7 +373,7 @@ func (s *Server) HandleConn(c net.Conn, isKCP bool) {
 		case <-ticker.C:
 			err := connection.Ping()
 			if err != nil {
-				cancel()
+				connection.cancel()
 			}
 		case <-ctx.Done():
 			s.RemoveConn(connection)
@@ -440,7 +442,14 @@ func (s *Server) RoundTrip(req *http.Request) (*http.Response, error) {
 		}
 	}
 
-	if len(conns) == 0 {
+	var goodConns []*Connection
+	for _, conn := range conns {
+		if conn.usable {
+			goodConns = append(goodConns, conn)
+		}
+	}
+
+	if len(goodConns) == 0 {
 		ln.Error(ErrNoSuchBackend, ln.F{
 			"action": "no_backend_connected",
 			"remote": req.RemoteAddr,
@@ -451,7 +460,7 @@ func (s *Server) RoundTrip(req *http.Request) (*http.Response, error) {
 		return nil, ErrNoSuchBackend
 	}
 
-	c := conns[rand.Intn(len(conns))]
+	c := goodConns[rand.Intn(len(goodConns))]
 
 	resp, err := c.RoundTrip(req)
 	if err != nil {
diff --git a/proto/route.pb.go b/proto/route.pb.go
index 9edcaec..2daaf04 100644
--- a/proto/route.pb.go
+++ b/proto/route.pb.go
@@ -219,6 +219,7 @@ type Backend struct {
 	Domain string  `protobuf:"bytes,4,opt,name=domain" json:"domain,omitempty"`
 	Phi    float32 `protobuf:"fixed32,5,opt,name=phi" json:"phi,omitempty"`
 	Host   string  `protobuf:"bytes,6,opt,name=host" json:"host,omitempty"`
+	Usable bool    `protobuf:"varint,7,opt,name=usable" json:"usable,omitempty"`
 }
 
 func (m *Backend) Reset()                    { *m = Backend{} }
@@ -268,6 +269,13 @@ func (m *Backend) GetHost() string {
 	return ""
 }
 
+func (m *Backend) GetUsable() bool {
+	if m != nil {
+		return m.Usable
+	}
+	return false
+}
+
 type BackendList struct {
 	Bs       *BackendSelector `protobuf:"bytes,1,opt,name=bs" json:"bs,omitempty"`
 	Backends []*Backend       `protobuf:"bytes,2,rep,name=backends" json:"backends,omitempty"`
@@ -814,40 +822,41 @@ var _Backends_serviceDesc = grpc.ServiceDesc{
 func init() { proto.RegisterFile("route.proto", fileDescriptor0) }
 
 var fileDescriptor0 = []byte{
-	// 553 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x8c, 0x53, 0x4f, 0x6f, 0xd3, 0x4e,
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-	0x94, 0x91, 0xa1, 0x7f, 0x20, 0x8f, 0x7e, 0xb9, 0x10, 0x72, 0x7e, 0xee, 0x73, 0x51, 0x0d, 0xd6,
-	0xa0, 0x96, 0x40, 0xe1, 0xe0, 0xe3, 0x7b, 0x5d, 0xf4, 0xaa, 0xac, 0x19, 0x19, 0xe1, 0xe0, 0xc3,
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-	0xff, 0x11, 0x4c, 0x9d, 0x1a, 0x00, 0x05, 0x00, 0x00,
+	// 565 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x8c, 0x53, 0x5d, 0x8b, 0xd3, 0x40,
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+	0xcc, 0xe1, 0x02, 0x5a, 0xf6, 0xe9, 0x14, 0xbe, 0x82, 0x06, 0x27, 0xec, 0x1f, 0xa9, 0xea, 0x63,
+	0xbd, 0x5f, 0x71, 0x85, 0x83, 0x97, 0xd0, 0xf8, 0x98, 0x17, 0x05, 0x9e, 0xd6, 0xd1, 0xc9, 0xa8,
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+	0xf1, 0x18, 0x05, 0x00, 0x00,
 }
diff --git a/proto/route.proto b/proto/route.proto
index a1c109c..130d4bb 100644
--- a/proto/route.proto
+++ b/proto/route.proto
@@ -121,6 +121,7 @@ message Backend {
   string domain = 4;
   float phi = 5;
   string host = 6;
+  bool usable = 7;
 }
 
 message BackendList {