diff --git a/common/net/address.go b/common/net/address.go
index e31384102..bb7a6466e 100644
--- a/common/net/address.go
+++ b/common/net/address.go
@@ -21,11 +21,17 @@ var (
 	LocalHostIPv6 = IPAddress([]byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1})
 )
 
+// AddressFamily is the type of address.
 type AddressFamily int
 
 const (
-	AddressFamilyIPv4   = AddressFamily(0)
-	AddressFamilyIPv6   = AddressFamily(1)
+	// AddressFamilyIPv4 represents address as IPv4
+	AddressFamilyIPv4 = AddressFamily(0)
+
+	// AddressFamilyIPv6 represents address as IPv6
+	AddressFamilyIPv6 = AddressFamily(1)
+
+	// AddressFamilyDomain represents address as Domain
 	AddressFamilyDomain = AddressFamily(2)
 )
 
diff --git a/common/net/destination.go b/common/net/destination.go
index 0675ab245..c495a5b01 100644
--- a/common/net/destination.go
+++ b/common/net/destination.go
@@ -11,6 +11,7 @@ type Destination struct {
 	Address Address
 }
 
+// DestinationFromAddr generates a Destination from a net address.
 func DestinationFromAddr(addr net.Addr) Destination {
 	switch addr := addr.(type) {
 	case *net.TCPAddr:
@@ -52,6 +53,7 @@ func (v Destination) IsValid() bool {
 	return v.Network != Network_Unknown
 }
 
+// AsDestination converts current Enpoint into Destination.
 func (v *Endpoint) AsDestination() Destination {
 	return Destination{
 		Network: v.Network,
diff --git a/common/net/network.go b/common/net/network.go
index 1a8bc417c..791b3d05c 100644
--- a/common/net/network.go
+++ b/common/net/network.go
@@ -46,7 +46,7 @@ func (v Network) URLPrefix() string {
 	}
 }
 
-// HashNetwork returns true if the given network is in v NetworkList.
+// HasNetwork returns true if the given network is in v NetworkList.
 func (v NetworkList) HasNetwork(network Network) bool {
 	for _, value := range v.Network {
 		if string(value) == string(network) {
@@ -60,6 +60,7 @@ func (v NetworkList) Get(idx int) Network {
 	return v.Network[idx]
 }
 
+// Size returns the number of networks in this network list.
 func (v NetworkList) Size() int {
 	return len(v.Network)
 }
diff --git a/common/net/port.go b/common/net/port.go
index 5df99b513..08327a579 100644
--- a/common/net/port.go
+++ b/common/net/port.go
@@ -63,6 +63,7 @@ func (v PortRange) Contains(port Port) bool {
 	return v.FromPort() <= port && port <= v.ToPort()
 }
 
+// SinglePortRange returns a PortRange contains a single port.
 func SinglePortRange(v Port) *PortRange {
 	return &PortRange{
 		From: uint32(v),
diff --git a/common/protocol/headers.go b/common/protocol/headers.go
index 1e7832a1c..259af8f95 100644
--- a/common/protocol/headers.go
+++ b/common/protocol/headers.go
@@ -7,6 +7,7 @@ import (
 	"v2ray.com/core/common/uuid"
 )
 
+// RequestCommand is a custom command in a proxy request.
 type RequestCommand byte
 
 const (