diff --git a/common/bufio/conn.go b/common/bufio/conn.go
index bde9bd5..e58d66a 100644
--- a/common/bufio/conn.go
+++ b/common/bufio/conn.go
@@ -30,7 +30,7 @@ func (w *ExtendedUDPConn) ReadPacket(buffer *buf.Buffer) (M.Socksaddr, error) {
 		return M.Socksaddr{}, err
 	}
 	buffer.Truncate(n)
-	return M.SocksaddrFromNetIP(addr), nil
+	return M.SocksaddrFromNetIP(addr).Unwrap(), nil
 }
 
 func (w *ExtendedUDPConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
@@ -58,7 +58,7 @@ func (w *ExtendedPacketConn) ReadPacket(buffer *buf.Buffer) (M.Socksaddr, error)
 	if err != nil {
 		return M.Socksaddr{}, err
 	}
-	return M.SocksaddrFromNet(addr), err
+	return M.SocksaddrFromNet(addr).Unwrap(), err
 }
 
 func (w *ExtendedPacketConn) WritePacket(buffer *buf.Buffer, destination M.Socksaddr) error {
diff --git a/common/metadata/addr.go b/common/metadata/addr.go
index 43865ef..3abe98a 100644
--- a/common/metadata/addr.go
+++ b/common/metadata/addr.go
@@ -6,6 +6,8 @@ import (
 	"strconv"
 	"strings"
 	"unsafe"
+
+	"github.com/sagernet/sing/common/debug"
 )
 
 type Socksaddr struct {
@@ -19,15 +21,15 @@ func (ap Socksaddr) Network() string {
 }
 
 func (ap Socksaddr) IsIP() bool {
-	return ap.Addr.IsValid() && ap.Fqdn == ""
+	return ap.Addr.IsValid()
 }
 
 func (ap Socksaddr) IsIPv4() bool {
-	return ap.Addr.Is4() || ap.Addr.Is4In6()
+	return ap.Addr.Is4()
 }
 
 func (ap Socksaddr) IsIPv6() bool {
-	return ap.Addr.Is6() && !ap.Addr.Is4In6()
+	return ap.Addr.Is6()
 }
 
 func (ap Socksaddr) Unwrap() Socksaddr {
@@ -41,7 +43,7 @@ func (ap Socksaddr) Unwrap() Socksaddr {
 }
 
 func (ap Socksaddr) IsFqdn() bool {
-	return !ap.Addr.IsValid() && IsDomainName(ap.Fqdn)
+	return IsDomainName(ap.Fqdn)
 }
 
 func (ap Socksaddr) IsValid() bool {
@@ -49,6 +51,9 @@ func (ap Socksaddr) IsValid() bool {
 }
 
 func (ap Socksaddr) AddrString() string {
+	if debug.Enabled {
+		ap.CheckBadAddr()
+	}
 	if ap.Addr.IsValid() {
 		return ap.Addr.String()
 	} else {
@@ -57,12 +62,18 @@ func (ap Socksaddr) AddrString() string {
 }
 
 func (ap Socksaddr) IPAddr() *net.IPAddr {
+	if debug.Enabled {
+		ap.CheckBadAddr()
+	}
 	return &net.IPAddr{
 		IP: ap.Addr.AsSlice(),
 	}
 }
 
 func (ap Socksaddr) TCPAddr() *net.TCPAddr {
+	if debug.Enabled {
+		ap.CheckBadAddr()
+	}
 	return &net.TCPAddr{
 		IP:   ap.Addr.AsSlice(),
 		Port: int(ap.Port),
@@ -70,6 +81,9 @@ func (ap Socksaddr) TCPAddr() *net.TCPAddr {
 }
 
 func (ap Socksaddr) UDPAddr() *net.UDPAddr {
+	if debug.Enabled {
+		ap.CheckBadAddr()
+	}
 	return &net.UDPAddr{
 		IP:   ap.Addr.AsSlice(),
 		Port: int(ap.Port),
@@ -77,24 +91,22 @@ func (ap Socksaddr) UDPAddr() *net.UDPAddr {
 }
 
 func (ap Socksaddr) AddrPort() netip.AddrPort {
+	if debug.Enabled {
+		ap.CheckBadAddr()
+	}
 	return *(*netip.AddrPort)(unsafe.Pointer(&ap))
 }
 
 func (ap Socksaddr) String() string {
+	if debug.Enabled {
+		ap.CheckBadAddr()
+	}
 	return net.JoinHostPort(ap.AddrString(), strconv.Itoa(int(ap.Port)))
 }
 
-func TCPAddr(ap netip.AddrPort) *net.TCPAddr {
-	return &net.TCPAddr{
-		IP:   ap.Addr().AsSlice(),
-		Port: int(ap.Port()),
-	}
-}
-
-func UDPAddr(ap netip.AddrPort) *net.UDPAddr {
-	return &net.UDPAddr{
-		IP:   ap.Addr().AsSlice(),
-		Port: int(ap.Port()),
+func (ap Socksaddr) CheckBadAddr() {
+	if ap.Addr.Is4In6() || ap.Addr.IsValid() && ap.Fqdn != "" {
+		panic("bad socksaddr")
 	}
 }
 
diff --git a/common/metadata/serializer.go b/common/metadata/serializer.go
index 6b5321b..98ed304 100644
--- a/common/metadata/serializer.go
+++ b/common/metadata/serializer.go
@@ -62,7 +62,7 @@ func (s *Serializer) WriteAddress(buffer *buf.Buffer, addr Socksaddr) error {
 		return err
 	}
 	if addr.Addr.IsValid() {
-		_, err = buffer.Write(addr.Unwrap().Addr.AsSlice())
+		_, err = buffer.Write(addr.Addr.AsSlice())
 	} else {
 		err = WriteSocksString(buffer, addr.Fqdn)
 	}
diff --git a/go.mod b/go.mod
index fabefb4..45d4d34 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,4 @@ module github.com/sagernet/sing
 
 go 1.18
 
-require golang.org/x/sys v0.0.0-20220913120320-3275c407cedc
+require golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8
diff --git a/go.sum b/go.sum
index 6b04132..25341eb 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,2 @@
-golang.org/x/sys v0.0.0-20220913120320-3275c407cedc h1:dpclq5m2YrqPGStKmtw7IcNbKLfbIqKXvNxDJKdIKYc=
-golang.org/x/sys v0.0.0-20220913120320-3275c407cedc/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8 h1:h+EGohizhe9XlX18rfpa8k8RAc5XyaeamM+0VHRd4lc=
+golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
diff --git a/protocol/http/addr.go b/protocol/http/addr.go
index 27ad1b2..61b673c 100644
--- a/protocol/http/addr.go
+++ b/protocol/http/addr.go
@@ -18,5 +18,5 @@ func SourceAddress(request *http.Request) M.Socksaddr {
 			}
 		}
 	}
-	return address
+	return address.Unwrap()
 }
diff --git a/protocol/socks/socks4/protocol.go b/protocol/socks/socks4/protocol.go
index 619e389..f5c8f7e 100644
--- a/protocol/socks/socks4/protocol.go
+++ b/protocol/socks/socks4/protocol.go
@@ -96,7 +96,7 @@ func WriteRequest(writer io.Writer, request Request) error {
 		binary.Write(buffer, binary.BigEndian, request.Destination.Port),
 	)
 	if request.Destination.IsIPv4() {
-		common.Must1(buffer.Write(request.Destination.Unwrap().Addr.AsSlice()))
+		common.Must1(buffer.Write(request.Destination.Addr.AsSlice()))
 	} else {
 		// 0.0.0.X
 		common.Must(buffer.WriteZeroN(3))
@@ -153,7 +153,7 @@ func WriteResponse(writer io.Writer, response Response) error {
 		buffer.WriteByte(0),
 		buffer.WriteByte(response.ReplyCode),
 		binary.Write(buffer, binary.BigEndian, response.Destination.Port),
-		common.Error(buffer.Write(response.Destination.Unwrap().Addr.AsSlice())),
+		common.Error(buffer.Write(response.Destination.Addr.AsSlice())),
 	)
 	return rw.WriteBytes(writer, buffer.Bytes())
 }