diff --git a/src/net/dial.go b/src/net/dial.go
index 0a7da408fe5..bed0b1e3e0c 100644
--- a/src/net/dial.go
+++ b/src/net/dial.go
@@ -135,23 +135,26 @@ func (d *Dialer) fallbackDelay() time.Duration {
 	}
 }
 
-func parseNetwork(ctx context.Context, net string) (afnet string, proto int, err error) {
-	i := last(net, ':')
+func parseNetwork(ctx context.Context, network string, needsProto bool) (afnet string, proto int, err error) {
+	i := last(network, ':')
 	if i < 0 { // no colon
-		switch net {
+		switch network {
 		case "tcp", "tcp4", "tcp6":
 		case "udp", "udp4", "udp6":
 		case "ip", "ip4", "ip6":
+			if needsProto {
+				return "", 0, UnknownNetworkError(network)
+			}
 		case "unix", "unixgram", "unixpacket":
 		default:
-			return "", 0, UnknownNetworkError(net)
+			return "", 0, UnknownNetworkError(network)
 		}
-		return net, 0, nil
+		return network, 0, nil
 	}
-	afnet = net[:i]
+	afnet = network[:i]
 	switch afnet {
 	case "ip", "ip4", "ip6":
-		protostr := net[i+1:]
+		protostr := network[i+1:]
 		proto, i, ok := dtoi(protostr)
 		if !ok || i != len(protostr) {
 			proto, err = lookupProtocol(ctx, protostr)
@@ -161,14 +164,14 @@ func parseNetwork(ctx context.Context, net string) (afnet string, proto int, err
 		}
 		return afnet, proto, nil
 	}
-	return "", 0, UnknownNetworkError(net)
+	return "", 0, UnknownNetworkError(network)
 }
 
 // resolveAddrList resolves addr using hint and returns a list of
 // addresses. The result contains at least one address when error is
 // nil.
 func (r *Resolver) resolveAddrList(ctx context.Context, op, network, addr string, hint Addr) (addrList, error) {
-	afnet, _, err := parseNetwork(ctx, network)
+	afnet, _, err := parseNetwork(ctx, network, true)
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/net/iprawsock.go b/src/net/iprawsock.go
index d994fc67c65..d69a303d786 100644
--- a/src/net/iprawsock.go
+++ b/src/net/iprawsock.go
@@ -71,7 +71,7 @@ func ResolveIPAddr(net, addr string) (*IPAddr, error) {
 	if net == "" { // a hint wildcard for Go 1.0 undocumented behavior
 		net = "ip"
 	}
-	afnet, _, err := parseNetwork(context.Background(), net)
+	afnet, _, err := parseNetwork(context.Background(), net, false)
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/net/iprawsock_posix.go b/src/net/iprawsock_posix.go
index 8f4b702e480..5d76818af9f 100644
--- a/src/net/iprawsock_posix.go
+++ b/src/net/iprawsock_posix.go
@@ -113,7 +113,7 @@ func (c *IPConn) writeMsg(b, oob []byte, addr *IPAddr) (n, oobn int, err error)
 }
 
 func dialIP(ctx context.Context, netProto string, laddr, raddr *IPAddr) (*IPConn, error) {
-	network, proto, err := parseNetwork(ctx, netProto)
+	network, proto, err := parseNetwork(ctx, netProto, true)
 	if err != nil {
 		return nil, err
 	}
@@ -133,7 +133,7 @@ func dialIP(ctx context.Context, netProto string, laddr, raddr *IPAddr) (*IPConn
 }
 
 func listenIP(ctx context.Context, netProto string, laddr *IPAddr) (*IPConn, error) {
-	network, proto, err := parseNetwork(ctx, netProto)
+	network, proto, err := parseNetwork(ctx, netProto, true)
 	if err != nil {
 		return nil, err
 	}
diff --git a/src/net/iprawsock_test.go b/src/net/iprawsock_test.go
index 5d33b26a91e..8972051f5d5 100644
--- a/src/net/iprawsock_test.go
+++ b/src/net/iprawsock_test.go
@@ -117,3 +117,75 @@ func TestIPConnRemoteName(t *testing.T) {
 		t.Fatalf("got %#v; want %#v", c.RemoteAddr(), raddr)
 	}
 }
+
+func TestDialListenIPArgs(t *testing.T) {
+	type test struct {
+		argLists   [][2]string
+		shouldFail bool
+	}
+	tests := []test{
+		{
+			argLists: [][2]string{
+				{"ip", "127.0.0.1"},
+				{"ip:", "127.0.0.1"},
+				{"ip::", "127.0.0.1"},
+				{"ip", "::1"},
+				{"ip:", "::1"},
+				{"ip::", "::1"},
+				{"ip4", "127.0.0.1"},
+				{"ip4:", "127.0.0.1"},
+				{"ip4::", "127.0.0.1"},
+				{"ip6", "::1"},
+				{"ip6:", "::1"},
+				{"ip6::", "::1"},
+			},
+			shouldFail: true,
+		},
+	}
+	if testableNetwork("ip") {
+		priv := test{shouldFail: false}
+		for _, tt := range []struct {
+			network, address string
+			args             [2]string
+		}{
+			{"ip4:47", "127.0.0.1", [2]string{"ip4:47", "127.0.0.1"}},
+			{"ip6:47", "::1", [2]string{"ip6:47", "::1"}},
+		} {
+			c, err := ListenPacket(tt.network, tt.address)
+			if err != nil {
+				continue
+			}
+			c.Close()
+			priv.argLists = append(priv.argLists, tt.args)
+		}
+		if len(priv.argLists) > 0 {
+			tests = append(tests, priv)
+		}
+	}
+
+	for _, tt := range tests {
+		for _, args := range tt.argLists {
+			_, err := Dial(args[0], args[1])
+			if tt.shouldFail != (err != nil) {
+				t.Errorf("Dial(%q, %q) = %v; want (err != nil) is %t", args[0], args[1], err, tt.shouldFail)
+			}
+			_, err = ListenPacket(args[0], args[1])
+			if tt.shouldFail != (err != nil) {
+				t.Errorf("ListenPacket(%q, %q) = %v; want (err != nil) is %t", args[0], args[1], err, tt.shouldFail)
+			}
+			a, err := ResolveIPAddr("ip", args[1])
+			if err != nil {
+				t.Errorf("ResolveIPAddr(\"ip\", %q) = %v", args[1], err)
+				continue
+			}
+			_, err = DialIP(args[0], nil, a)
+			if tt.shouldFail != (err != nil) {
+				t.Errorf("DialIP(%q, %v) = %v; want (err != nil) is %t", args[0], a, err, tt.shouldFail)
+			}
+			_, err = ListenIP(args[0], a)
+			if tt.shouldFail != (err != nil) {
+				t.Errorf("ListenIP(%q, %v) = %v; want (err != nil) is %t", args[0], a, err, tt.shouldFail)
+			}
+		}
+	}
+}