diff --git a/internal/client/storage.go b/internal/client/storage.go
index d6de62c3..46597cec 100644
--- a/internal/client/storage.go
+++ b/internal/client/storage.go
@@ -2,12 +2,14 @@ package client
 
 import (
 	"fmt"
+	"net/netip"
 	"slices"
 
 	"github.com/AdguardTeam/dnsproxy/proxy"
 	"github.com/AdguardTeam/dnsproxy/upstream"
 	"github.com/AdguardTeam/golibs/container"
 	"github.com/AdguardTeam/golibs/errors"
+	"github.com/AdguardTeam/golibs/log"
 )
 
 // Storage contains information about persistent and runtime clients.
@@ -17,6 +19,9 @@ type Storage struct {
 
 	// index contains information about persistent clients.
 	index *Index
+
+	// runtimeIndex contains information about runtime clients.
+	runtimeIndex map[netip.Addr]*Runtime
 }
 
 // NewStorage returns initialized client storage.
@@ -24,8 +29,9 @@ func NewStorage(clientTags []string) (s *Storage) {
 	allTags := container.NewMapSet(clientTags...)
 
 	return &Storage{
-		allTags: allTags,
-		index:   NewIndex(),
+		allTags:      allTags,
+		index:        NewIndex(),
+		runtimeIndex: map[netip.Addr]*Runtime{},
 	}
 }
 
@@ -52,11 +58,16 @@ func (s *Storage) check(p *Persistent) (err error) {
 		return errors.Error("id required")
 	}
 
-	_, err = proxy.ParseUpstreamsConfig(p.Upstreams, &upstream.Options{})
+	conf, err := proxy.ParseUpstreamsConfig(p.Upstreams, &upstream.Options{})
 	if err != nil {
 		return fmt.Errorf("invalid upstream servers: %w", err)
 	}
 
+	err = conf.Close()
+	if err != nil {
+		log.Error("client: closing upstream config: %s", err)
+	}
+
 	for _, t := range p.Tags {
 		if !s.allTags.Has(t) {
 			return fmt.Errorf("invalid tag: %q", t)
@@ -104,3 +115,50 @@ func (s *Storage) Update(p, n *Persistent) (err error) {
 
 	return nil
 }
+
+// ClientRuntime returns the saved runtime client by ip.  If no such client
+// exists, returns nil.
+func (s *Storage) ClientRuntime(ip netip.Addr) (rc *Runtime) {
+	return s.runtimeIndex[ip]
+}
+
+// AddRuntime saves the runtime client information in the storage.  IP address
+// of a client must be unique.  rc must not be nil.
+func (s *Storage) AddRuntime(rc *Runtime) {
+	ip := rc.Addr()
+	s.runtimeIndex[ip] = rc
+}
+
+// SizeRuntime returns the number of the runtime clients.
+func (s *Storage) SizeRuntime() (n int) {
+	return len(s.runtimeIndex)
+}
+
+// RangeRuntime calls f for each runtime client in an undefined order.
+func (s *Storage) RangeRuntime(f func(rc *Runtime) (cont bool)) {
+	for _, rc := range s.runtimeIndex {
+		if !f(rc) {
+			return
+		}
+	}
+}
+
+// DeleteRuntime removes the runtime client by ip.
+func (s *Storage) DeleteRuntime(ip netip.Addr) {
+	delete(s.runtimeIndex, ip)
+}
+
+// DeleteBySource removes all runtime clients that have information only from
+// the specified source and returns the number of removed clients.
+func (s *Storage) DeleteBySource(src Source) (n int) {
+	for ip, rc := range s.runtimeIndex {
+		rc.unset(src)
+
+		if rc.isEmpty() {
+			delete(s.runtimeIndex, ip)
+			n++
+		}
+	}
+
+	return n
+}