diff --git a/internal/networkio/datagram.go b/internal/networkio/datagram.go
index 42b9fbe6..efd3ffe0 100644
--- a/internal/networkio/datagram.go
+++ b/internal/networkio/datagram.go
@@ -5,15 +5,15 @@ import (
 	"net"
 )
 
-// DatagramConn wraps a datagram socket and implements OpenVPN framing.
-type DatagramConn struct {
+// datagramConn wraps a datagram socket and implements OpenVPN framing.
+type datagramConn struct {
 	net.Conn
 }
 
-var _ FramingConn = &DatagramConn{}
+var _ FramingConn = &datagramConn{}
 
 // ReadRawPacket implements FramingConn
-func (c *DatagramConn) ReadRawPacket() ([]byte, error) {
+func (c *datagramConn) ReadRawPacket() ([]byte, error) {
 	buffer := make([]byte, math.MaxUint16) // maximum UDP datagram size
 	count, err := c.Read(buffer)
 	if err != nil {
@@ -24,7 +24,7 @@ func (c *DatagramConn) ReadRawPacket() ([]byte, error) {
 }
 
 // WriteRawPacket implements FramingConn
-func (c *DatagramConn) WriteRawPacket(pkt []byte) error {
+func (c *datagramConn) WriteRawPacket(pkt []byte) error {
 	if len(pkt) > math.MaxUint16 {
 		return ErrPacketTooLarge
 	}
diff --git a/internal/networkio/dialer.go b/internal/networkio/dialer.go
index 1ee9391c..ae87a27e 100644
--- a/internal/networkio/dialer.go
+++ b/internal/networkio/dialer.go
@@ -42,8 +42,8 @@ func (d *Dialer) DialContext(ctx context.Context, network, address string) (Fram
 	// wrap the conn and return
 	switch conn.LocalAddr().Network() {
 	case "udp", "udp4", "udp6":
-		return &DatagramConn{conn}, nil
+		return &datagramConn{conn}, nil
 	default:
-		return &StreamConn{conn}, nil
+		return &streamConn{conn}, nil
 	}
 }
diff --git a/internal/networkio/stream.go b/internal/networkio/stream.go
index 381895f0..2fb22726 100644
--- a/internal/networkio/stream.go
+++ b/internal/networkio/stream.go
@@ -8,15 +8,15 @@ import (
 	"net"
 )
 
-// StreamConn wraps a stream socket and implements OpenVPN framing.
-type StreamConn struct {
+// streamConn wraps a stream socket and implements OpenVPN framing.
+type streamConn struct {
 	net.Conn
 }
 
-var _ FramingConn = &StreamConn{}
+var _ FramingConn = &streamConn{}
 
 // ReadRawPacket implements FramingConn
-func (c *StreamConn) ReadRawPacket() ([]byte, error) {
+func (c *streamConn) ReadRawPacket() ([]byte, error) {
 	lenbuf := make([]byte, 2)
 	if _, err := io.ReadFull(c.Conn, lenbuf); err != nil {
 		return nil, err
@@ -33,7 +33,7 @@ func (c *StreamConn) ReadRawPacket() ([]byte, error) {
 var ErrPacketTooLarge = errors.New("openvpn: packet too large")
 
 // WriteRawPacket implements FramingConn
-func (c *StreamConn) WriteRawPacket(pkt []byte) error {
+func (c *streamConn) WriteRawPacket(pkt []byte) error {
 	if len(pkt) > math.MaxUint16 {
 		return ErrPacketTooLarge
 	}