diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..97fd741c18c273f7496e5520c65aa0ef88b6de75
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+go-mmproxy
\ No newline at end of file
diff --git a/buffers.go b/buffers.go
index 1d2ec457b33e075c26d86814a8b930f3af743a2a..d51bf71e14d0127e2874a15e8999a3411f7f88f9 100644
--- a/buffers.go
+++ b/buffers.go
@@ -12,7 +12,7 @@ import (
 var buffers sync.Pool
 
 func init() {
-	buffers.New = func() interface{} { return make([]byte, math.MaxUint16) }
+	buffers.New = func() any { return make([]byte, math.MaxUint16) }
 }
 
 func GetBuffer() []byte {
@@ -20,5 +20,5 @@ func GetBuffer() []byte {
 }
 
 func PutBuffer(buf []byte) {
-	buffers.Put(buf)
+	buffers.Put(buf) // nolint:staticcheck
 }
diff --git a/go.mod b/go.mod
index bb726f7982c82fb802931f3d4f2c1a0072fb0d51..7c9850844c66c9d944a4eb3685cccc2b8cd3e3c5 100644
--- a/go.mod
+++ b/go.mod
@@ -1,10 +1,3 @@
 module github.com/path-network/go-mmproxy
 
 go 1.21
-
-require go.uber.org/zap v1.15.0
-
-require (
-	go.uber.org/atomic v1.6.0 // indirect
-	go.uber.org/multierr v1.5.0 // indirect
-)
diff --git a/go.sum b/go.sum
deleted file mode 100644
index a4450f41aea49009676f008faa983287bfed39ac..0000000000000000000000000000000000000000
--- a/go.sum
+++ /dev/null
@@ -1,52 +0,0 @@
-github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
-github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
-github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
-github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
-github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
-github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
-github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-go.uber.org/atomic v1.6.0 h1:Ezj3JGmsOnG1MoRWQkPBsKLe9DwWD9QeXzTRzzldNVk=
-go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
-go.uber.org/multierr v1.5.0 h1:KCa4XfM8CWFCpxXRGok+Q0SS/0XBhMDbHHGABQLvD2A=
-go.uber.org/multierr v1.5.0/go.mod h1:FeouvMocqHpRaaGuG9EjoKcStLC43Zu/fmqdUMPcKYU=
-go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee h1:0mgffUl7nfd+FpvXMVz4IDEaUSmT1ysygQC7qYo7sG4=
-go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
-go.uber.org/zap v1.15.0 h1:ZZCA22JRF2gQE5FoNmhmrf7jeJJ2uhqDUNRYKm8dvmM=
-go.uber.org/zap v1.15.0/go.mod h1:Mb2vm2krFEG5DV0W9qcHBYFtp/Wku1cvYaqPsS/WYfc=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
-golang.org/x/crypto v0.0.0-20190510104115-cbcb75029529/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
-golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
-golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
-golang.org/x/mod v0.0.0-20190513183733-4bf6d317e70e/go.mod h1:mXi4GBBbnImb6dmsKGUJ2LatrhH/nqhxcFungHvyanc=
-golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
-golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgwSSTFct+R/Kf4OFW1sUzUTQQTgfc=
-golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5 h1:hKsoRgsbwY1NafxrwTs+k64bikrLBkAgPir1TNCj3Zs=
-golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=
-gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-honnef.co/go/tools v0.0.1-2019.2.3 h1:3JgtbtFHMiCmsznwGVTUWbgGov+pVqnlf1dEJTNAXeM=
-honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
diff --git a/main.go b/main.go
index 395f4644b41b8259bb340d7b0b58316c015a3f9a..9062dfa588019f51877d24f56597d50abc242beb 100644
--- a/main.go
+++ b/main.go
@@ -7,13 +7,11 @@ package main
 import (
 	"bufio"
 	"flag"
-	"log"
+	"log/slog"
 	"net"
 	"os"
 	"syscall"
 	"time"
-
-	"go.uber.org/zap"
 )
 
 type options struct {
@@ -26,7 +24,7 @@ type options struct {
 	allowedSubnetsPath string
 	AllowedSubnets     []*net.IPNet
 	Listeners          int
-	Logger             *zap.Logger
+	Logger             *slog.Logger
 	udpCloseAfter      int
 	UDPCloseAfter      time.Duration
 }
@@ -50,8 +48,8 @@ func init() {
 }
 
 func listen(listenerNum int, errors chan<- error) {
-	logger := Opts.Logger.With(zap.Int("listenerNum", listenerNum),
-		zap.String("protocol", Opts.Protocol), zap.String("listenAdr", Opts.ListenAddr))
+	logger := Opts.Logger.With(slog.Int("listenerNum", listenerNum),
+		slog.String("protocol", Opts.Protocol), slog.String("listenAdr", Opts.ListenAddr))
 
 	listenConfig := net.ListenConfig{}
 	if Opts.Listeners > 1 {
@@ -87,57 +85,49 @@ func loadAllowedSubnets() error {
 			return err
 		}
 		Opts.AllowedSubnets = append(Opts.AllowedSubnets, ipNet)
-		Opts.Logger.Info("allowed subnet", zap.String("subnet", ipNet.String()))
+		Opts.Logger.Info("allowed subnet", slog.String("subnet", ipNet.String()))
 	}
 
 	return nil
 }
 
-func initLogger() error {
-	logConfig := zap.NewProductionConfig()
-	if Opts.Verbose > 0 {
-		logConfig.Level.SetLevel(zap.DebugLevel)
-	}
-
-	l, err := logConfig.Build()
-	if err == nil {
-		Opts.Logger = l
-	}
-	return err
-}
-
 func main() {
 	flag.Parse()
-	if err := initLogger(); err != nil {
-		log.Fatalf("Failed to initialize logging: %s", err.Error())
+	lvl := slog.LevelInfo
+	if Opts.Verbose > 0 {
+		lvl = slog.LevelDebug
 	}
-	defer Opts.Logger.Sync()
+	Opts.Logger = slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{Level: lvl}))
 
 	if Opts.allowedSubnetsPath != "" {
 		if err := loadAllowedSubnets(); err != nil {
-			Opts.Logger.Fatal("failed to load allowed subnets file",
-				zap.String("path", Opts.allowedSubnetsPath), zap.Error(err))
+			Opts.Logger.Error("failed to load allowed subnets file", "path", Opts.allowedSubnetsPath, "error", err)
 		}
 	}
 
 	if Opts.Protocol != "tcp" && Opts.Protocol != "udp" {
-		Opts.Logger.Fatal("--protocol has to be one of udp, tcp", zap.String("protocol", Opts.Protocol))
+		Opts.Logger.Error("--protocol has to be one of udp, tcp", slog.String("protocol", Opts.Protocol))
+		os.Exit(1)
 	}
 
 	if Opts.Mark < 0 {
-		Opts.Logger.Fatal("--mark has to be >= 0", zap.Int("mark", Opts.Mark))
+		Opts.Logger.Error("--mark has to be >= 0", slog.Int("mark", Opts.Mark))
+		os.Exit(1)
 	}
 
 	if Opts.Verbose < 0 {
-		Opts.Logger.Fatal("-v has to be >= 0", zap.Int("verbose", Opts.Verbose))
+		Opts.Logger.Error("-v has to be >= 0", slog.Int("verbose", Opts.Verbose))
+		os.Exit(1)
 	}
 
 	if Opts.Listeners < 1 {
-		Opts.Logger.Fatal("--listeners has to be >= 1")
+		Opts.Logger.Error("--listeners has to be >= 1")
+		os.Exit(1)
 	}
 
 	if Opts.udpCloseAfter < 0 {
-		Opts.Logger.Fatal("--close-after has to be >= 0", zap.Int("close-after", Opts.udpCloseAfter))
+		Opts.Logger.Error("--close-after has to be >= 0", slog.Int("close-after", Opts.udpCloseAfter))
+		os.Exit(1)
 	}
 	Opts.UDPCloseAfter = time.Duration(Opts.udpCloseAfter) * time.Second
 
diff --git a/tcp.go b/tcp.go
index a206256818277a81691498bccc73584a88bab237..f8eb1eea0757e58a4e3510006fc5b2203800c8fe 100644
--- a/tcp.go
+++ b/tcp.go
@@ -7,9 +7,8 @@ package main
 import (
 	"context"
 	"io"
+	"log/slog"
 	"net"
-
-	"go.uber.org/zap"
 )
 
 func tcpCopyData(dst net.Conn, src net.Conn, ch chan<- error) {
@@ -17,13 +16,13 @@ func tcpCopyData(dst net.Conn, src net.Conn, ch chan<- error) {
 	ch <- err
 }
 
-func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
+func tcpHandleConnection(conn net.Conn, logger *slog.Logger) {
 	defer conn.Close()
-	logger = logger.With(zap.String("remoteAddr", conn.RemoteAddr().String()),
-		zap.String("localAddr", conn.LocalAddr().String()))
+	logger = logger.With(slog.String("remoteAddr", conn.RemoteAddr().String()),
+		slog.String("localAddr", conn.LocalAddr().String()))
 
 	if !CheckOriginAllowed(conn.RemoteAddr().(*net.TCPAddr).IP) {
-		logger.Debug("connection origin not in allowed subnets", zap.Bool("dropConnection", true))
+		logger.Debug("connection origin not in allowed subnets", slog.Bool("dropConnection", true))
 		return
 	}
 
@@ -40,13 +39,13 @@ func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
 
 	n, err := conn.Read(buffer)
 	if err != nil {
-		logger.Debug("failed to read PROXY header", zap.Error(err), zap.Bool("dropConnection", true))
+		logger.Debug("failed to read PROXY header", "error", err, slog.Bool("dropConnection", true))
 		return
 	}
 
 	saddr, _, restBytes, err := PROXYReadRemoteAddr(buffer[:n], TCP)
 	if err != nil {
-		logger.Debug("failed to parse PROXY header", zap.Error(err), zap.Bool("dropConnection", true))
+		logger.Debug("failed to parse PROXY header", "error", err, slog.Bool("dropConnection", true))
 		return
 	}
 
@@ -63,7 +62,7 @@ func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
 	if saddr != nil {
 		clientAddr = saddr.String()
 	}
-	logger = logger.With(zap.String("clientAddr", clientAddr), zap.String("targetAddr", targetAddr))
+	logger = logger.With(slog.String("clientAddr", clientAddr), slog.String("targetAddr", targetAddr))
 	if Opts.Verbose > 1 {
 		logger.Debug("successfully parsed PROXY header")
 	}
@@ -74,7 +73,7 @@ func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
 	}
 	upstreamConn, err := dialer.Dial("tcp", targetAddr)
 	if err != nil {
-		logger.Debug("failed to establish upstream connection", zap.Error(err), zap.Bool("dropConnection", true))
+		logger.Debug("failed to establish upstream connection", "error", err, slog.Bool("dropConnection", true))
 		return
 	}
 
@@ -84,13 +83,13 @@ func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
 	}
 
 	if err := conn.(*net.TCPConn).SetNoDelay(true); err != nil {
-		logger.Debug("failed to set nodelay on downstream connection", zap.Error(err), zap.Bool("dropConnection", true))
+		logger.Debug("failed to set nodelay on downstream connection", "error", err, slog.Bool("dropConnection", true))
 	} else if Opts.Verbose > 1 {
 		logger.Debug("successfully set NoDelay on downstream connection")
 	}
 
 	if err := upstreamConn.(*net.TCPConn).SetNoDelay(true); err != nil {
-		logger.Debug("failed to set nodelay on upstream connection", zap.Error(err), zap.Bool("dropConnection", true))
+		logger.Debug("failed to set nodelay on upstream connection", "error", err, slog.Bool("dropConnection", true))
 	} else if Opts.Verbose > 1 {
 		logger.Debug("successfully set NoDelay on upstream connection")
 	}
@@ -99,7 +98,7 @@ func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
 		n, err := upstreamConn.Write(restBytes)
 		if err != nil {
 			logger.Debug("failed to write data to upstream connection",
-				zap.Error(err), zap.Bool("dropConnection", true))
+				"error", err, slog.Bool("dropConnection", true))
 			return
 		}
 		restBytes = restBytes[n:]
@@ -114,17 +113,17 @@ func tcpHandleConnection(conn net.Conn, logger *zap.Logger) {
 
 	err = <-outErr
 	if err != nil {
-		logger.Debug("connection broken", zap.Error(err), zap.Bool("dropConnection", true))
+		logger.Debug("connection broken", "error", err, slog.Bool("dropConnection", true))
 	} else if Opts.Verbose > 1 {
 		logger.Debug("connection closing")
 	}
 }
 
-func TCPListen(listenConfig *net.ListenConfig, logger *zap.Logger, errors chan<- error) {
+func TCPListen(listenConfig *net.ListenConfig, logger *slog.Logger, errors chan<- error) {
 	ctx := context.Background()
 	ln, err := listenConfig.Listen(ctx, "tcp", Opts.ListenAddr)
 	if err != nil {
-		logger.Error("failed to bind listener", zap.Error(err))
+		logger.Error("failed to bind listener", "error", err)
 		errors <- err
 		return
 	}
@@ -134,7 +133,7 @@ func TCPListen(listenConfig *net.ListenConfig, logger *zap.Logger, errors chan<-
 	for {
 		conn, err := ln.Accept()
 		if err != nil {
-			logger.Error("failed to accept new connection", zap.Error(err))
+			logger.Error("failed to accept new connection", "error", err)
 			errors <- err
 			return
 		}
diff --git a/udp.go b/udp.go
index 923bc647fd87d60cc1f3db823dfe771133fcf484..5eb2054c8ff37d97e04ad9dc2a3c92e449c95c5b 100644
--- a/udp.go
+++ b/udp.go
@@ -6,12 +6,12 @@ package main
 
 import (
 	"context"
+	"errors"
+	"log/slog"
 	"net"
 	"sync/atomic"
 	"syscall"
 	"time"
-
-	"go.uber.org/zap"
 )
 
 type udpConnection struct {
@@ -19,7 +19,7 @@ type udpConnection struct {
 	clientAddr     *net.UDPAddr
 	downstreamAddr *net.UDPAddr
 	upstream       *net.UDPConn
-	logger         *zap.Logger
+	logger         *slog.Logger
 }
 
 func udpCloseAfterInactivity(conn *udpConnection, socketClosures chan<- string) {
@@ -41,7 +41,7 @@ func udpCloseAfterInactivity(conn *udpConnection, socketClosures chan<- string)
 func udpCopyFromUpstream(downstream net.PacketConn, conn *udpConnection) {
 	rawConn, err := conn.upstream.SyscallConn()
 	if err != nil {
-		conn.logger.Error("failed to retrieve raw connection from upstream socket", zap.Error(err))
+		conn.logger.Error("failed to retrieve raw connection from upstream socket", "error", err)
 		return
 	}
 
@@ -53,7 +53,7 @@ func udpCopyFromUpstream(downstream net.PacketConn, conn *udpConnection) {
 
 		for {
 			n, _, serr := syscall.Recvfrom(int(fd), buf, syscall.MSG_DONTWAIT)
-			if serr == syscall.EWOULDBLOCK {
+			if errors.Is(serr, syscall.EWOULDBLOCK) {
 				return false
 			}
 			if serr != nil {
@@ -77,11 +77,11 @@ func udpCopyFromUpstream(downstream net.PacketConn, conn *udpConnection) {
 		err = syscallErr
 	}
 	if err != nil {
-		conn.logger.Debug("failed to read from upstream", zap.Error(err))
+		conn.logger.Debug("failed to read from upstream", "error", err)
 	}
 }
 
-func udpGetSocketFromMap(downstream net.PacketConn, downstreamAddr, saddr net.Addr, logger *zap.Logger,
+func udpGetSocketFromMap(downstream net.PacketConn, downstreamAddr, saddr net.Addr, logger *slog.Logger,
 	connMap map[string]*udpConnection, socketClosures chan<- string) (*udpConnection, error) {
 	connKey := ""
 	if saddr != nil {
@@ -97,10 +97,10 @@ func udpGetSocketFromMap(downstream net.PacketConn, downstreamAddr, saddr net.Ad
 		targetAddr = Opts.TargetAddr4
 	}
 
-	logger = logger.With(zap.String("downstreamAddr", downstreamAddr.String()), zap.String("targetAddr", targetAddr))
+	logger = logger.With(slog.String("downstreamAddr", downstreamAddr.String()), slog.String("targetAddr", targetAddr))
 	dialer := net.Dialer{LocalAddr: saddr}
 	if saddr != nil {
-		logger = logger.With(zap.String("clientAddr", saddr.String()))
+		logger = logger.With(slog.String("clientAddr", saddr.String()))
 		dialer.Control = DialUpstreamControl(saddr.(*net.UDPAddr).Port)
 	}
 
@@ -110,7 +110,7 @@ func udpGetSocketFromMap(downstream net.PacketConn, downstreamAddr, saddr net.Ad
 
 	conn, err := dialer.Dial("udp", targetAddr)
 	if err != nil {
-		logger.Debug("failed to connect to upstream", zap.Error(err))
+		logger.Debug("failed to connect to upstream", "error", err)
 		return nil, err
 	}
 
@@ -129,11 +129,11 @@ func udpGetSocketFromMap(downstream net.PacketConn, downstreamAddr, saddr net.Ad
 	return udpConn, nil
 }
 
-func UDPListen(listenConfig *net.ListenConfig, logger *zap.Logger, errors chan<- error) {
+func UDPListen(listenConfig *net.ListenConfig, logger *slog.Logger, errors chan<- error) {
 	ctx := context.Background()
 	ln, err := listenConfig.ListenPacket(ctx, "udp", Opts.ListenAddr)
 	if err != nil {
-		logger.Error("failed to bind listener", zap.Error(err))
+		logger.Error("failed to bind listener", "error", err)
 		errors <- err
 		return
 	}
@@ -149,18 +149,18 @@ func UDPListen(listenConfig *net.ListenConfig, logger *zap.Logger, errors chan<-
 	for {
 		n, remoteAddr, err := ln.ReadFrom(buffer)
 		if err != nil {
-			logger.Error("failed to read from socket", zap.Error(err))
+			logger.Error("failed to read from socket", "error", err)
 			continue
 		}
 
 		if !CheckOriginAllowed(remoteAddr.(*net.UDPAddr).IP) {
-			logger.Debug("packet origin not in allowed subnets", zap.String("remoteAddr", remoteAddr.String()))
+			logger.Debug("packet origin not in allowed subnets", slog.String("remoteAddr", remoteAddr.String()))
 			continue
 		}
 
 		saddr, _, restBytes, err := PROXYReadRemoteAddr(buffer[:n], UDP)
 		if err != nil {
-			logger.Debug("failed to parse PROXY header", zap.Error(err), zap.String("remoteAddr", remoteAddr.String()))
+			logger.Debug("failed to parse PROXY header", "error", err, slog.String("remoteAddr", remoteAddr.String()))
 			continue
 		}
 
@@ -184,7 +184,7 @@ func UDPListen(listenConfig *net.ListenConfig, logger *zap.Logger, errors chan<-
 
 		_, err = conn.upstream.Write(restBytes)
 		if err != nil {
-			conn.logger.Error("failed to write to upstream socket", zap.Error(err))
+			conn.logger.Error("failed to write to upstream socket", "error", err)
 		}
 	}
 }
diff --git a/utils.go b/utils.go
index 2610bb74300f4ecdbcd162d709bee32575054e6b..02d7490c511cca540a6f9a05d4892ce60b6c1d15 100644
--- a/utils.go
+++ b/utils.go
@@ -38,32 +38,36 @@ func DialUpstreamControl(sport int) func(string, string, syscall.RawConn) error
 			if Opts.Protocol == "tcp" {
 				syscallErr = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_TCP, syscall.TCP_SYNCNT, 2)
 				if syscallErr != nil {
-					syscallErr = fmt.Errorf("setsockopt(IPPROTO_TCP, TCP_SYNCTNT, 2): %s", syscallErr.Error())
+					syscallErr = fmt.Errorf("setsockopt(IPPROTO_TCP, TCP_SYNCTNT, 2): %w", syscallErr)
 					return
 				}
 			}
 
 			syscallErr = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, syscall.IP_TRANSPARENT, 1)
 			if syscallErr != nil {
-				syscallErr = fmt.Errorf("setsockopt(IPPROTO_IP, IP_TRANSPARENT, 1): %s", syscallErr.Error())
+				syscallErr = fmt.Errorf("setsockopt(IPPROTO_IP, IP_TRANSPARENT, 1): %w", syscallErr)
 				return
 			}
 
 			syscallErr = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
 			if syscallErr != nil {
-				syscallErr = fmt.Errorf("setsockopt(SOL_SOCKET, SO_REUSEADDR, 1): %s", syscallErr.Error())
+				syscallErr = fmt.Errorf("setsockopt(SOL_SOCKET, SO_REUSEADDR, 1): %w", syscallErr)
 				return
 			}
 
 			if sport == 0 {
 				ipBindAddressNoPort := 24
-				syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, ipBindAddressNoPort, 1)
+				syscallErr = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP, ipBindAddressNoPort, 1)
+				if syscallErr != nil {
+					syscallErr = fmt.Errorf("setsockopt(SOL_SOCKET, IPPROTO_IP, %d): %w", Opts.Mark, syscallErr)
+					return
+				}
 			}
 
 			if Opts.Mark != 0 {
 				syscallErr = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_MARK, Opts.Mark)
 				if syscallErr != nil {
-					syscallErr = fmt.Errorf("setsockopt(SOL_SOCK, SO_MARK, %d): %s", Opts.Mark, syscallErr.Error())
+					syscallErr = fmt.Errorf("setsockopt(SOL_SOCK, SO_MARK, %d): %w", Opts.Mark, syscallErr)
 					return
 				}
 			}
@@ -71,7 +75,7 @@ func DialUpstreamControl(sport int) func(string, string, syscall.RawConn) error
 			if network == "tcp6" || network == "udp6" {
 				syscallErr = syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IPV6, syscall.IPV6_V6ONLY, 0)
 				if syscallErr != nil {
-					syscallErr = fmt.Errorf("setsockopt(IPPROTO_IP, IPV6_ONLY, 0): %s", syscallErr.Error())
+					syscallErr = fmt.Errorf("setsockopt(IPPROTO_IP, IPV6_ONLY, 0): %w", syscallErr)
 					return
 				}
 			}