diff --git a/.goreleaser.yml b/.goreleaser.yml
index e1aaff0..2c81f7d 100644
--- a/.goreleaser.yml
+++ b/.goreleaser.yml
@@ -1,7 +1,7 @@
 builds:
   - skip: true
 checksum:
-  name_template: '{{ .ProjectName }}_{{ .Version }}_sha256_checksums.txt'
+  name_template: '{{ .ProjectName }}_sha256_checksums.txt'
   algorithm: sha256
   extra_files:
   - glob: ./release/packages/*
diff --git a/Makefile b/Makefile
index ae1a013..d3f09bd 100644
--- a/Makefile
+++ b/Makefile
@@ -16,6 +16,9 @@ file:
 fmt:
 	go fmt ./...
 
+vet:
+	go vet ./...
+
 frps:
 	env CGO_ENABLED=0 go build -trimpath -ldflags "$(LDFLAGS)" -o bin/frps ./cmd/frps
 
@@ -37,7 +40,7 @@ e2e:
 e2e-trace:
 	DEBUG=true LOG_LEVEL=trace ./hack/run-e2e.sh
 
-alltest: gotest e2e
+alltest: vet gotest e2e
 	
 clean:
 	rm -f ./bin/frpc
diff --git a/Release.md b/Release.md
index 9be2af7..78f9d43 100644
--- a/Release.md
+++ b/Release.md
@@ -1,8 +1,7 @@
 ### New
 
-* Support go http pprof.
+* Added new parameter `config_dir` in frpc to run multiple client instances in one process.
 
-### Improve
+### Fix
 
-* Change underlying TCP connection keepalive interval to 2 hours.
-* Create new connection to server for `sudp` visitor when needed, to avoid frequent reconnections.
+* Equal sign in environment variables causes parsing error.
diff --git a/client/proxy/proxy.go b/client/proxy/proxy.go
index 0fdecec..df5e87d 100644
--- a/client/proxy/proxy.go
+++ b/client/proxy/proxy.go
@@ -366,7 +366,7 @@ func (pxy *XTCPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
 	// Listen for clientConn's address and wait for visitor connection
 	lConn, err := net.ListenUDP("udp", laddr)
 	if err != nil {
-		xl.Error("listen on visitorConn's local adress error: %v", err)
+		xl.Error("listen on visitorConn's local address error: %v", err)
 		return
 	}
 	defer lConn.Close()
diff --git a/client/service.go b/client/service.go
index 11e369c..30bd3f8 100644
--- a/client/service.go
+++ b/client/service.go
@@ -19,9 +19,11 @@ import (
 	"crypto/tls"
 	"fmt"
 	"io"
+	"math/rand"
 	"net"
 	"runtime"
 	"strconv"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -36,11 +38,17 @@ import (
 	"github.com/fatedier/frp/pkg/util/util"
 	"github.com/fatedier/frp/pkg/util/version"
 	"github.com/fatedier/frp/pkg/util/xlog"
+	"github.com/fatedier/golib/crypto"
 	libdial "github.com/fatedier/golib/net/dial"
 
 	fmux "github.com/hashicorp/yamux"
 )
 
+func init() {
+	crypto.DefaultSalt = "frp"
+	rand.Seed(time.Now().UnixNano())
+}
+
 // Service is a client service.
 type Service struct {
 	// uniq id got from frps, attach it in loginMsg
@@ -98,6 +106,21 @@ func (svr *Service) GetController() *Control {
 func (svr *Service) Run() error {
 	xl := xlog.FromContextSafe(svr.ctx)
 
+	// set custom DNSServer
+	if svr.cfg.DNSServer != "" {
+		dnsAddr := svr.cfg.DNSServer
+		if !strings.Contains(dnsAddr, ":") {
+			dnsAddr += ":53"
+		}
+		// Change default dns server for frpc
+		net.DefaultResolver = &net.Resolver{
+			PreferGo: true,
+			Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+				return net.Dial("udp", dnsAddr)
+			},
+		}
+	}
+
 	// login to frps
 	for {
 		conn, session, err := svr.login()
@@ -333,7 +356,14 @@ func (svr *Service) ReloadConf(pxyCfgs map[string]config.ProxyConf, visitorCfgs
 	svr.visitorCfgs = visitorCfgs
 	svr.cfgMu.Unlock()
 
-	return svr.ctl.ReloadConf(pxyCfgs, visitorCfgs)
+	svr.ctlMu.RLock()
+	ctl := svr.ctl
+	svr.ctlMu.RUnlock()
+
+	if ctl != nil {
+		return svr.ctl.ReloadConf(pxyCfgs, visitorCfgs)
+	}
+	return nil
 }
 
 func (svr *Service) Close() {
@@ -342,8 +372,12 @@ func (svr *Service) Close() {
 
 func (svr *Service) GracefulClose(d time.Duration) {
 	atomic.StoreUint32(&svr.exit, 1)
+
+	svr.ctlMu.RLock()
 	if svr.ctl != nil {
 		svr.ctl.GracefulClose(d)
 	}
+	svr.ctlMu.RUnlock()
+
 	svr.cancel()
 }
diff --git a/cmd/frpc/main.go b/cmd/frpc/main.go
index 2c1e015..f9a6c25 100644
--- a/cmd/frpc/main.go
+++ b/cmd/frpc/main.go
@@ -15,18 +15,10 @@
 package main
 
 import (
-	"math/rand"
-	"time"
-
 	_ "github.com/fatedier/frp/assets/frpc"
 	"github.com/fatedier/frp/cmd/frpc/sub"
-
-	"github.com/fatedier/golib/crypto"
 )
 
 func main() {
-	crypto.DefaultSalt = "frp"
-	rand.Seed(time.Now().UnixNano())
-
 	sub.Execute()
 }
diff --git a/cmd/frpc/sub/root.go b/cmd/frpc/sub/root.go
index d03cdd1..f8d7eb1 100644
--- a/cmd/frpc/sub/root.go
+++ b/cmd/frpc/sub/root.go
@@ -15,13 +15,14 @@
 package sub
 
 import (
-	"context"
 	"fmt"
+	"io/fs"
 	"net"
 	"os"
 	"os/signal"
+	"path/filepath"
 	"strconv"
-	"strings"
+	"sync"
 	"syscall"
 	"time"
 
@@ -41,6 +42,7 @@ const (
 
 var (
 	cfgFile     string
+	cfgDir      string
 	showVersion bool
 
 	serverAddr      string
@@ -72,15 +74,12 @@ var (
 	bindPort          int
 
 	tlsEnable bool
-
-	kcpDoneCh chan struct{}
 )
 
 func init() {
 	rootCmd.PersistentFlags().StringVarP(&cfgFile, "config", "c", "./frpc.ini", "config file of frpc")
+	rootCmd.PersistentFlags().StringVarP(&cfgDir, "config_dir", "", "", "config directory, run one frpc service for each file in config directory")
 	rootCmd.PersistentFlags().BoolVarP(&showVersion, "version", "v", false, "version of frpc")
-
-	kcpDoneCh = make(chan struct{})
 }
 
 func RegisterCommonFlags(cmd *cobra.Command) {
@@ -104,6 +103,32 @@ var rootCmd = &cobra.Command{
 			return nil
 		}
 
+		// If cfgDir is not empty, run multiple frpc service for each config file in cfgDir.
+		// Note that it's only designed for testing. It's not guaranteed to be stable.
+		if cfgDir != "" {
+			var wg sync.WaitGroup
+			filepath.WalkDir(cfgDir, func(path string, d fs.DirEntry, err error) error {
+				if err != nil {
+					return nil
+				}
+				if d.IsDir() {
+					return nil
+				}
+				wg.Add(1)
+				time.Sleep(time.Millisecond)
+				go func() {
+					defer wg.Done()
+					err := runClient(path)
+					if err != nil {
+						fmt.Printf("frpc service error for config file [%s]\n", path)
+					}
+				}()
+				return nil
+			})
+			wg.Wait()
+			return nil
+		}
+
 		// Do not show command usage here.
 		err := runClient(cfgFile)
 		if err != nil {
@@ -120,12 +145,12 @@ func Execute() {
 	}
 }
 
-func handleSignal(svr *client.Service) {
-	ch := make(chan os.Signal)
+func handleSignal(svr *client.Service, doneCh chan struct{}) {
+	ch := make(chan os.Signal, 1)
 	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
 	<-ch
 	svr.GracefulClose(500 * time.Millisecond)
-	close(kcpDoneCh)
+	close(doneCh)
 }
 
 func parseClientCommonCfgFromCmd() (cfg config.ClientCommonConf, err error) {
@@ -182,18 +207,9 @@ func startService(
 	log.InitLog(cfg.LogWay, cfg.LogFile, cfg.LogLevel,
 		cfg.LogMaxDays, cfg.DisableLogColor)
 
-	if cfg.DNSServer != "" {
-		s := cfg.DNSServer
-		if !strings.Contains(s, ":") {
-			s += ":53"
-		}
-		// Change default dns server for frpc
-		net.DefaultResolver = &net.Resolver{
-			PreferGo: true,
-			Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
-				return net.Dial("udp", s)
-			},
-		}
+	if cfgFile != "" {
+		log.Trace("start frpc service for config file [%s]", cfgFile)
+		defer log.Trace("frpc service for config file [%s] stopped", cfgFile)
 	}
 	svr, errRet := client.NewService(cfg, pxyCfgs, visitorCfgs, cfgFile)
 	if errRet != nil {
@@ -201,9 +217,10 @@ func startService(
 		return
 	}
 
+	kcpDoneCh := make(chan struct{})
 	// Capture the exit signal if we use kcp.
 	if cfg.Protocol == "kcp" {
-		go handleSignal(svr)
+		go handleSignal(svr, kcpDoneCh)
 	}
 
 	err = svr.Run()
diff --git a/conf/frpc_full.ini b/conf/frpc_full.ini
index 913c971..a0e7dca 100644
--- a/conf/frpc_full.ini
+++ b/conf/frpc_full.ini
@@ -105,7 +105,7 @@ tls_enable = true
 # specify a dns server, so frpc will use this instead of default one
 # dns_server = 8.8.8.8
 
-# proxy names you want to start seperated by ','
+# proxy names you want to start separated by ','
 # default is empty, means all proxies
 # start = ssh,dns
 
diff --git a/go.mod b/go.mod
index ea9d6b9..0a92dfb 100644
--- a/go.mod
+++ b/go.mod
@@ -16,7 +16,7 @@ require (
 	github.com/leodido/go-urn v1.2.1 // indirect
 	github.com/onsi/ginkgo v1.16.4
 	github.com/onsi/gomega v1.13.0
-	github.com/pires/go-proxyproto v0.5.0
+	github.com/pires/go-proxyproto v0.6.2
 	github.com/pquerna/cachecontrol v0.0.0-20180517163645-1555304b9b35 // indirect
 	github.com/prometheus/client_golang v1.11.0
 	github.com/rodaine/table v1.0.1
diff --git a/go.sum b/go.sum
index cfe79d3..433f03e 100644
--- a/go.sum
+++ b/go.sum
@@ -300,8 +300,8 @@ github.com/onsi/gomega v1.13.0/go.mod h1:lRk9szgn8TxENtWd0Tp4c3wjlRfMTMH27I+3Je4
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
-github.com/pires/go-proxyproto v0.5.0 h1:A4Jv4ZCaV3AFJeGh5mGwkz4iuWUYMlQ7IoO/GTuSuLo=
-github.com/pires/go-proxyproto v0.5.0/go.mod h1:Odh9VFOZJCf9G8cLW5o435Xf1J95Jw9Gw5rnCjcwzAY=
+github.com/pires/go-proxyproto v0.6.2 h1:KAZ7UteSOt6urjme6ZldyFm4wDe/z0ZUP0Yv0Dos0d8=
+github.com/pires/go-proxyproto v0.6.2/go.mod h1:Odh9VFOZJCf9G8cLW5o435Xf1J95Jw9Gw5rnCjcwzAY=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
diff --git a/pkg/config/client.go b/pkg/config/client.go
index 27a47a2..f503711 100644
--- a/pkg/config/client.go
+++ b/pkg/config/client.go
@@ -133,7 +133,7 @@ type ClientCommonConf struct {
 	// It only works when "tls_enable" is valid and tls configuration of server
 	// has been specified.
 	TLSTrustedCaFile string `ini:"tls_trusted_ca_file" json:"tls_trusted_ca_file"`
-	// TLSServerName specifices the custom server name of tls certificate. By
+	// TLSServerName specifies the custom server name of tls certificate. By
 	// default, server name if same to ServerAddr.
 	TLSServerName string `ini:"tls_server_name" json:"tls_server_name"`
 	// By default, frpc will connect frps with first custom byte if tls is enabled.
diff --git a/pkg/config/value.go b/pkg/config/value.go
index 41c6c65..e44fbd6 100644
--- a/pkg/config/value.go
+++ b/pkg/config/value.go
@@ -29,11 +29,11 @@ func init() {
 	glbEnvs = make(map[string]string)
 	envs := os.Environ()
 	for _, env := range envs {
-		kv := strings.Split(env, "=")
-		if len(kv) != 2 {
+		pair := strings.SplitN(env, "=", 2)
+		if len(pair) != 2 {
 			continue
 		}
-		glbEnvs[kv[0]] = kv[1]
+		glbEnvs[pair[0]] = pair[1]
 	}
 }
 
diff --git a/pkg/util/version/version.go b/pkg/util/version/version.go
index 07d0da2..67e6bab 100644
--- a/pkg/util/version/version.go
+++ b/pkg/util/version/version.go
@@ -19,7 +19,7 @@ import (
 	"strings"
 )
 
-var version string = "0.41.0"
+var version string = "0.42.0"
 
 func Full() string {
 	return version
diff --git a/pkg/util/vhost/http.go b/pkg/util/vhost/http.go
index b9dc32d..b720862 100644
--- a/pkg/util/vhost/http.go
+++ b/pkg/util/vhost/http.go
@@ -89,7 +89,7 @@ func NewHTTPReverseProxy(option HTTPReverseProxyOptions, vhostRouter *Routers) *
 		BufferPool: newWrapPool(),
 		ErrorLog:   log.New(newWrapLogger(), "", 0),
 		ErrorHandler: func(rw http.ResponseWriter, req *http.Request, err error) {
-			frpLog.Warn("do http proxy request error: %v", err)
+			frpLog.Warn("do http proxy request [host: %s] error: %v", req.Host, err)
 			rw.WriteHeader(http.StatusNotFound)
 			rw.Write(getNotFoundPageContent())
 		},
diff --git a/server/control.go b/server/control.go
index 0974061..74a3cfa 100644
--- a/server/control.go
+++ b/server/control.go
@@ -258,7 +258,7 @@ func (ctl *Control) GetWorkConn() (workConn net.Conn, err error) {
 		case workConn, ok = <-ctl.workConnCh:
 			if !ok {
 				err = frpErr.ErrCtlClosed
-				xl.Warn("no work connections avaiable, %v", err)
+				xl.Warn("no work connections available, %v", err)
 				return
 			}
 
diff --git a/test/e2e/plugin/server.go b/test/e2e/plugin/server.go
index b972f78..2af1eba 100644
--- a/test/e2e/plugin/server.go
+++ b/test/e2e/plugin/server.go
@@ -150,7 +150,7 @@ var _ = Describe("[Feature: Server-Plugins]", func() {
 			type = tcp
 			local_port = {{ .%s }}
 			remote_port = 0
-			`, framework.TCPEchoServerPort, remotePort)
+			`, framework.TCPEchoServerPort)
 
 			f.RunProcesses([]string{serverConf}, []string{clientConf})