diff --git a/balancer/balancer.go b/balancer/balancer.go
index b0a00b11..6430a58b 100644
--- a/balancer/balancer.go
+++ b/balancer/balancer.go
@@ -9,13 +9,18 @@ import (
 	"github.com/sagernet/sing-box/adapter"
 	"github.com/sagernet/sing-box/log"
 	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing/common"
+	N "github.com/sagernet/sing/common/network"
 )
 
 var _ Balancer = (*rttBasedBalancer)(nil)
 
 // Balancer is interface for load balancers
 type Balancer interface {
-	Pick() string
+	// Pick picks a qualified nodes
+	Pick(network string) string
+	// Networks returns the supported network types
+	Networks() []string
 }
 
 type rttBasedBalancer struct {
@@ -49,8 +54,46 @@ func newRTTBasedBalancer(
 }
 
 // Select selects qualified nodes
-func (s *rttBasedBalancer) Pick() string {
-	nodes := s.HealthCheck.NodesByCategory()
+func (s *rttBasedBalancer) Networks() []string {
+	hasTCP, hasUDP := false, false
+	nodes := s.HealthCheck.NodesByCategory("")
+	for _, node := range nodes.Qualified {
+		if !hasTCP && common.Contains(node.Networks, N.NetworkTCP) {
+			hasTCP = true
+		}
+		if !hasUDP && common.Contains(node.Networks, N.NetworkUDP) {
+			hasUDP = true
+		}
+		if hasTCP && hasUDP {
+			break
+		}
+	}
+	if !hasTCP && !hasUDP {
+		for _, node := range nodes.Untested {
+			if !hasTCP && common.Contains(node.Networks, N.NetworkTCP) {
+				hasTCP = true
+			}
+			if !hasUDP && common.Contains(node.Networks, N.NetworkUDP) {
+				hasUDP = true
+			}
+			if hasTCP && hasUDP {
+				break
+			}
+		}
+	}
+	switch {
+	case hasTCP && hasUDP:
+		return []string{N.NetworkTCP, N.NetworkUDP}
+	case hasTCP:
+		return []string{N.NetworkTCP}
+	default:
+		return []string{N.NetworkUDP}
+	}
+}
+
+// Select selects qualified nodes
+func (s *rttBasedBalancer) Pick(network string) string {
+	nodes := s.HealthCheck.NodesByCategory(network)
 	var candidates []*Node
 	if len(nodes.Qualified) > 0 {
 		candidates = nodes.Qualified
diff --git a/balancer/healthcheck.go b/balancer/healthcheck.go
index 260dd59c..ece6f0bc 100644
--- a/balancer/healthcheck.go
+++ b/balancer/healthcheck.go
@@ -22,7 +22,13 @@ type HealthCheck struct {
 	logger log.Logger
 
 	options *option.HealthCheckSettings
-	results map[string]*rttStorage
+	results map[string]*result
+}
+
+type result struct {
+	// tag      string
+	networks []string
+	*rttStorage
 }
 
 // NewHealthCheck creates a new HealthPing with settings
@@ -51,7 +57,7 @@ func NewHealthCheck(router adapter.Router, tags []string, logger log.Logger, con
 		router:  router,
 		tags:    tags,
 		options: config,
-		results: make(map[string]*rttStorage),
+		results: make(map[string]*result),
 		logger:  logger,
 	}
 }
diff --git a/balancer/healthcheck_nodes.go b/balancer/healthcheck_nodes.go
index 5245fce4..aac4cf90 100644
--- a/balancer/healthcheck_nodes.go
+++ b/balancer/healthcheck_nodes.go
@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing/common"
 )
 
 // CategorizedNodes holds the categorized nodes
@@ -13,8 +14,9 @@ type CategorizedNodes struct {
 	Failed, Untested       []*Node
 }
 
-// NodesByCategory returns the categorized nodes
-func (h *HealthCheck) NodesByCategory() *CategorizedNodes {
+// NodesByCategory returns the categorized nodes for specific network.
+// If network is empty, all nodes are returned.
+func (h *HealthCheck) NodesByCategory(network string) *CategorizedNodes {
 	h.Lock()
 	defer h.Unlock()
 	if h == nil || len(h.results) == 0 {
@@ -27,9 +29,13 @@ func (h *HealthCheck) NodesByCategory() *CategorizedNodes {
 		Untested:    make([]*Node, 0, len(h.results)),
 	}
 	for tag, result := range h.results {
+		if network != "" && !common.Contains(result.networks, network) {
+			continue
+		}
 		node := &Node{
 			Tag:      tag,
-			RTTStats: result.Get(),
+			Networks: result.networks,
+			RTTStats: result.rttStorage.Get(),
 		}
 		switch {
 		case node.RTTStats.All == 0:
@@ -72,15 +78,18 @@ func (h *HealthCheck) refreshNodes() []adapter.Outbound {
 		tag := node.Tag()
 		tags[tag] = struct{}{}
 		// make it known to the health check results
-		r, ok := h.results[tag]
+		_, ok := h.results[tag]
 		if !ok {
 			// validity is 2 times to sampling period, since the check are
 			// distributed in the time line randomly, in extreme cases,
 			// previous checks are distributed on the left, and latters
 			// on the right
 			validity := time.Duration(h.options.Interval) * time.Duration(h.options.SamplingCount) * 2
-			r = newRTTStorage(h.options.SamplingCount, validity)
-			h.results[tag] = r
+			h.results[tag] = &result{
+				// tag:        tag,
+				networks:   node.Network(),
+				rttStorage: newRTTStorage(h.options.SamplingCount, validity),
+			}
 		}
 	}
 	// remove unused rttStorage
diff --git a/balancer/node.go b/balancer/node.go
index a052f60e..e0134c62 100644
--- a/balancer/node.go
+++ b/balancer/node.go
@@ -11,6 +11,7 @@ var healthPingStatsUntested = RTTStats{
 
 // Node is a banalcer node with health check result
 type Node struct {
-	Tag string
+	Tag      string
+	Networks []string
 	RTTStats
 }
diff --git a/outbound/balancer.go b/outbound/balancer.go
index c85fd1ba..b7931192 100644
--- a/outbound/balancer.go
+++ b/outbound/balancer.go
@@ -49,23 +49,16 @@ func NewBalancer(
 }
 
 // Network implements adapter.Outbound
-//
-// FIXME: logic issue:
-// picked node is very likely to be different between first "Network() assetion"
-// then "NewConnection()", maybe we need to keep the picked node in the context?
-// that requests to change the Network() signature of the interface of
-// adapter.Outbound
 func (s *Balancer) Network() []string {
-	picked := s.pick()
-	if picked == nil {
+	if s.Balancer == nil {
 		return []string{N.NetworkTCP, N.NetworkUDP}
 	}
-	return picked.Network()
+	return s.Balancer.Networks()
 }
 
 // Now implements adapter.OutboundGroup
 func (s *Balancer) Now() string {
-	return s.pick().Tag()
+	return s.pick("").Tag()
 }
 
 // All implements adapter.OutboundGroup
@@ -75,22 +68,22 @@ func (s *Balancer) All() []string {
 
 // DialContext implements adapter.Outbound
 func (s *Balancer) DialContext(ctx context.Context, network string, destination M.Socksaddr) (net.Conn, error) {
-	return s.pick().DialContext(ctx, network, destination)
+	return s.pick(network).DialContext(ctx, network, destination)
 }
 
 // ListenPacket implements adapter.Outbound
 func (s *Balancer) ListenPacket(ctx context.Context, destination M.Socksaddr) (net.PacketConn, error) {
-	return s.pick().ListenPacket(ctx, destination)
+	return s.pick(N.NetworkUDP).ListenPacket(ctx, destination)
 }
 
 // NewConnection implements adapter.Outbound
 func (s *Balancer) NewConnection(ctx context.Context, conn net.Conn, metadata adapter.InboundContext) error {
-	return s.pick().NewConnection(ctx, conn, metadata)
+	return s.pick(N.NetworkTCP).NewConnection(ctx, conn, metadata)
 }
 
 // NewPacketConnection implements adapter.Outbound
 func (s *Balancer) NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata adapter.InboundContext) error {
-	return s.pick().NewPacketConnection(ctx, conn, metadata)
+	return s.pick(N.NetworkUDP).NewPacketConnection(ctx, conn, metadata)
 }
 
 // initialize inits the balancer
@@ -119,8 +112,8 @@ func (s *Balancer) setBalancer(b balancer.Balancer) error {
 	return nil
 }
 
-func (s *Balancer) pick() adapter.Outbound {
-	tag := s.pickTag()
+func (s *Balancer) pick(network string) adapter.Outbound {
+	tag := s.pickTag(network)
 	if tag == "" {
 		return s.fallback
 	}
@@ -131,12 +124,12 @@ func (s *Balancer) pick() adapter.Outbound {
 	return outbound
 }
 
-func (s *Balancer) pickTag() string {
+func (s *Balancer) pickTag(network string) string {
 	if s.Balancer == nil {
 		// not started yet, pick a random one
 		return s.randomTag()
 	}
-	tag := s.Balancer.Pick()
+	tag := s.Balancer.Pick(network)
 	if tag == "" {
 		return ""
 	}