diff --git a/.golangci.yml b/.golangci.yml
index 10bd9b3..6ce6ccf 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -90,6 +90,9 @@ issues:
     - linters: [godot]
       source: "\\/\\/\\s+}"
 
+    - linters: [gci]
+      source: "#nosec"
+
 linters:
   enable-all: true
   disable:
@@ -102,6 +105,10 @@ linters:
     - gomnd
     - goerr113
     - testpackage
+    - errorlint
+    - wrapcheck
+    - exhaustivestruct
+    - nlreturn
 
 run:
   skip-dirs:
diff --git a/client_test.go b/client_test.go
index 829e365..146ee38 100644
--- a/client_test.go
+++ b/client_test.go
@@ -442,11 +442,9 @@ func TestDial(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer func() {
-		if err = c.Close(); err != nil {
-			t.Error(err)
-		}
-	}()
+	if err = c.Close(); err != nil {
+		t.Error(err)
+	}
 }
 
 func TestDialError(t *testing.T) {
@@ -455,6 +453,7 @@ func TestDialError(t *testing.T) {
 		t.Fatal("error expected")
 	}
 }
+
 func TestClientCloseErr(t *testing.T) {
 	response := MustBuild(TransactionID, BindingSuccess)
 	response.Encode()
@@ -472,11 +471,9 @@ func TestClientCloseErr(t *testing.T) {
 	if err != nil {
 		log.Fatal(err)
 	}
-	defer func() {
-		if err, ok := c.Close().(CloseErr); !ok || err.AgentErr != io.ErrUnexpectedEOF {
-			t.Error("unexpected close err")
-		}
-	}()
+	if err, ok := c.Close().(CloseErr); !ok || err.AgentErr != io.ErrUnexpectedEOF {
+		t.Error("unexpected close err")
+	}
 }
 
 func TestWithNoConnClose(t *testing.T) {
@@ -618,13 +615,15 @@ func TestClientFinalizer(t *testing.T) {
 	}
 	clientFinalizer(c)
 	reader := bufio.NewScanner(buf)
-	var lines int
-	var expectedLines = []string{
-		"client: called finalizer on non-closed client: client not initialized",
-		"client: called finalizer on non-closed client",
-		"client: called finalizer on non-closed client: failed to close: " +
-			"<nil> (connection), unexpected EOF (agent)",
-	}
+	var (
+		lines         int
+		expectedLines = []string{
+			"client: called finalizer on non-closed client: client not initialized",
+			"client: called finalizer on non-closed client",
+			"client: called finalizer on non-closed client: failed to close: " +
+				"<nil> (connection), unexpected EOF (agent)",
+		}
+	)
 	for reader.Scan() {
 		if reader.Text() != expectedLines[lines] {
 			t.Error(reader.Text(), "!=", expectedLines[lines])
@@ -855,6 +854,7 @@ func TestClient_DoConcurrent(t *testing.T) {
 		1, 5, 10, 25, 100, 500,
 	} {
 		t.Run(fmt.Sprintf("%d", concurrency), func(t *testing.T) {
+			t.Parallel()
 			testClientDoConcurrent(t, concurrency)
 		})
 	}
diff --git a/cmd/stun-bench/main.go b/cmd/stun-bench/main.go
index bd662ce..85b8f95 100644
--- a/cmd/stun-bench/main.go
+++ b/cmd/stun-bench/main.go
@@ -20,7 +20,7 @@ import (
 
 var (
 	workers    = flag.Int("w", runtime.GOMAXPROCS(0), "concurrent workers")
-	addr       = flag.String("addr", fmt.Sprintf("localhost"), "target address")
+	addr       = flag.String("addr", "localhost", "target address")
 	port       = flag.Int("port", stun.DefaultPort, "target port")
 	duration   = flag.Duration("d", time.Minute, "benchmark duration")
 	network    = flag.String("net", "udp", "protocol to use (udp, tcp)")
diff --git a/cmd/stun-traversal/main.go b/cmd/stun-traversal/main.go
index 8dee571..4183b9d 100644
--- a/cmd/stun-traversal/main.go
+++ b/cmd/stun-traversal/main.go
@@ -13,9 +13,7 @@ import (
 	"gortc.io/stun"
 )
 
-var (
-	server = flag.String("server", fmt.Sprintf("gortc.io:3478"), "Stun server address")
-)
+var server = flag.String("server", "gortc.io:3478", "Stun server address")
 
 const (
 	udp           = "udp4"
diff --git a/fuzz.go b/fuzz.go
index 71790b1..2cb9b59 100644
--- a/fuzz.go
+++ b/fuzz.go
@@ -7,9 +7,7 @@ import (
 	"fmt"
 )
 
-var (
-	m = New()
-)
+var m = New()
 
 // FuzzMessage is go-fuzz endpoint for message.
 func FuzzMessage(data []byte) int {
@@ -96,7 +94,7 @@ func FuzzSetters(data []byte) int {
 		{new(MappedAddress), AttrMappedAddress},
 		{new(Realm), AttrRealm},
 	}
-	var firstByte = byte(0)
+	firstByte := byte(0)
 	if len(data) > 0 {
 		firstByte = data[0]
 	}
diff --git a/integrity_test.go b/integrity_test.go
index c19467c..97f5d72 100644
--- a/integrity_test.go
+++ b/integrity_test.go
@@ -102,6 +102,7 @@ func BenchmarkMessageIntegrity_AddTo(b *testing.B) {
 		m.Reset()
 	}
 }
+
 func BenchmarkMessageIntegrity_Check(b *testing.B) {
 	m := new(Message)
 	// TODO: Find a way to make this test zero-alloc without excessive pre-alloc.
diff --git a/message.go b/message.go
index 1211897..08e0487 100644
--- a/message.go
+++ b/message.go
@@ -416,7 +416,7 @@ const (
 var (
 	// Binding request message type.
 	BindingRequest = NewType(MethodBinding, ClassRequest)
-	// Binding success response message type
+	// Binding success response message type.
 	BindingSuccess = NewType(MethodBinding, ClassSuccessResponse)
 	// Binding error response message type.
 	BindingError = NewType(MethodBinding, ClassErrorResponse)
diff --git a/message_test.go b/message_test.go
index 32bf0b3..f3720ea 100644
--- a/message_test.go
+++ b/message_test.go
@@ -64,7 +64,7 @@ func BenchmarkMessage_Write(b *testing.B) {
 }
 
 func TestMessageType_Value(t *testing.T) {
-	var tests = []struct {
+	tests := []struct {
 		in  MessageType
 		out uint16
 	}{
@@ -82,7 +82,7 @@ func TestMessageType_Value(t *testing.T) {
 }
 
 func TestMessageType_ReadValue(t *testing.T) {
-	var tests = []struct {
+	tests := []struct {
 		in  uint16
 		out MessageType
 	}{
@@ -100,7 +100,7 @@ func TestMessageType_ReadValue(t *testing.T) {
 }
 
 func TestMessageType_ReadWriteValue(t *testing.T) {
-	var tests = []MessageType{
+	tests := []MessageType{
 		{Method: MethodBinding, Class: ClassRequest},
 		{Method: MethodBinding, Class: ClassSuccessResponse},
 		{Method: MethodBinding, Class: ClassErrorResponse},
@@ -197,8 +197,10 @@ func TestMessage_AttrLengthLessThanHeader(t *testing.T) {
 
 func TestMessage_AttrSizeLessThanLength(t *testing.T) {
 	mType := MessageType{Method: MethodBinding, Class: ClassRequest}
-	messageAttribute := RawAttribute{Length: 4,
-		Value: []byte{1, 2, 3, 4}, Type: 0x1,
+	messageAttribute := RawAttribute{
+		Length: 4,
+		Value:  []byte{1, 2, 3, 4},
+		Type:   0x1,
 	}
 	messageAttributes := Attributes{
 		messageAttribute,
@@ -497,7 +499,7 @@ func TestIsMessage(t *testing.T) {
 	NewSoftware("software").AddTo(m)
 	m.WriteHeader()
 
-	var tt = [...]struct {
+	tt := [...]struct {
 		in  []byte
 		out bool
 	}{
@@ -506,9 +508,11 @@ func TestIsMessage(t *testing.T) {
 		{[]byte{1, 2, 4}, false},                    // 2
 		{[]byte{1, 2, 4, 5, 6, 7, 8, 9, 20}, false}, // 3
 		{m.Raw, true},                               // 5
-		{[]byte{0, 0, 0, 0, 33, 18,
+		{[]byte{
+			0, 0, 0, 0, 33, 18,
 			164, 66, 0, 0, 0, 0, 0,
-			0, 0, 0, 0, 0, 0, 0, 0}, true}, // 6
+			0, 0, 0, 0, 0, 0, 0, 0,
+		}, true}, // 6
 	}
 	for i, v := range tt {
 		if got := IsMessage(v.in); got != v.out {