diff --git a/app/router/condition.go b/app/router/condition.go
index cf188686b..54fe9264b 100644
--- a/app/router/condition.go
+++ b/app/router/condition.go
@@ -144,7 +144,7 @@ func (m *MultiGeoIPMatcher) Apply(ctx context.Context) bool {
 
 	dest := m.destFunc(ctx)
 
-	if dest.IsValid() && (dest.Address.Family().IsIPv4() || dest.Address.Family().IsIPv6()) {
+	if dest.IsValid() && dest.Address.Family().IsIP() {
 		ips = append(ips, dest.Address.IP())
 	} else if resolver, ok := ResolvedIPsFromContext(ctx); ok {
 		resolvedIPs := resolver.Resolve()
diff --git a/common/net/address.go b/common/net/address.go
index da15b803b..1794ce7ff 100644
--- a/common/net/address.go
+++ b/common/net/address.go
@@ -35,16 +35,6 @@ const (
 	AddressFamilyDomain = AddressFamily(2)
 )
 
-// Either returns true if current AddressFamily matches any of the AddressFamilies provided.
-func (af AddressFamily) Either(fs ...AddressFamily) bool {
-	for _, f := range fs {
-		if af == f {
-			return true
-		}
-	}
-	return false
-}
-
 // IsIPv4 returns true if current AddressFamily is IPv4.
 func (af AddressFamily) IsIPv4() bool {
 	return af == AddressFamilyIPv4
@@ -55,6 +45,11 @@ func (af AddressFamily) IsIPv6() bool {
 	return af == AddressFamilyIPv6
 }
 
+// IsIP returns true if current AddressFamily is IPv6 or IPv4.
+func (af AddressFamily) IsIP() bool {
+	return af == AddressFamilyIPv4 || af == AddressFamilyIPv6
+}
+
 // IsDomain returns true if current AddressFamily is Domain.
 func (af AddressFamily) IsDomain() bool {
 	return af == AddressFamilyDomain
diff --git a/common/protocol/address.go b/common/protocol/address.go
index a3c628d4d..5bd974d49 100644
--- a/common/protocol/address.go
+++ b/common/protocol/address.go
@@ -213,7 +213,7 @@ func (p *addressParser) readAddress(b *buf.Buffer, reader io.Reader) (net.Addres
 		domain := string(b.BytesFrom(-domainLength))
 		if maybeIPPrefix(domain[0]) {
 			addr := net.ParseAddress(domain)
-			if addr.Family().IsIPv4() || addr.Family().IsIPv6() {
+			if addr.Family().IsIP() {
 				return addr, nil
 			}
 		}
diff --git a/transport/internet/websocket/hub.go b/transport/internet/websocket/hub.go
index bbbbe06f5..5dcb12364 100644
--- a/transport/internet/websocket/hub.go
+++ b/transport/internet/websocket/hub.go
@@ -41,7 +41,7 @@ func (h *requestHandler) ServeHTTP(writer http.ResponseWriter, request *http.Req
 
 	forwardedAddrs := http_proto.ParseXForwardedFor(request.Header)
 	remoteAddr := conn.RemoteAddr()
-	if len(forwardedAddrs) > 0 && forwardedAddrs[0].Family().Either(net.AddressFamilyIPv4, net.AddressFamilyIPv6) {
+	if len(forwardedAddrs) > 0 && forwardedAddrs[0].Family().IsIP() {
 		remoteAddr.(*net.TCPAddr).IP = forwardedAddrs[0].IP()
 	}