diff --git a/src/net/iprawsock.go b/src/net/iprawsock.go
index 00f59631a2a57..c4b54f00c4e6e 100644
--- a/src/net/iprawsock.go
+++ b/src/net/iprawsock.go
@@ -91,7 +91,7 @@ func ResolveIPAddr(network, address string) (*IPAddr, error) {
 	if err != nil {
 		return nil, err
 	}
-	return addrs.first(isIPv4).(*IPAddr), nil
+	return addrs.forResolve(network, address).(*IPAddr), nil
 }
 
 // IPConn is the implementation of the Conn and PacketConn interfaces
diff --git a/src/net/ipsock.go b/src/net/ipsock.go
index 7dafcaf630093..947bdf34897e7 100644
--- a/src/net/ipsock.go
+++ b/src/net/ipsock.go
@@ -50,7 +50,7 @@ func supportsIPv4map() bool {
 // An addrList represents a list of network endpoint addresses.
 type addrList []Addr
 
-// isIPv4 returns true if the Addr contains an IPv4 address.
+// isIPv4 reports whether addr contains an IPv4 address.
 func isIPv4(addr Addr) bool {
 	switch addr := addr.(type) {
 	case *TCPAddr:
@@ -63,6 +63,28 @@ func isIPv4(addr Addr) bool {
 	return false
 }
 
+// isNotIPv4 reports whether addr does not contain an IPv4 address.
+func isNotIPv4(addr Addr) bool { return !isIPv4(addr) }
+
+// forResolve returns the most appropriate address in address for
+// a call to ResolveTCPAddr, ResolveUDPAddr, or ResolveIPAddr.
+// IPv4 is preferred, unless addr contains an IPv6 literal.
+func (addrs addrList) forResolve(network, addr string) Addr {
+	var want6 bool
+	switch network {
+	case "ip":
+		// IPv6 literal (addr does NOT contain a port)
+		want6 = count(addr, ':') > 0
+	case "tcp", "udp":
+		// IPv6 literal. (addr contains a port, so look for '[')
+		want6 = count(addr, '[') > 0
+	}
+	if want6 {
+		return addrs.first(isNotIPv4)
+	}
+	return addrs.first(isIPv4)
+}
+
 // first returns the first address which satisfies strategy, or if
 // none do, then the first address of any kind.
 func (addrs addrList) first(strategy func(Addr) bool) Addr {
diff --git a/src/net/main_test.go b/src/net/main_test.go
index bbf32cfcd945c..3e7a85ad2d9fc 100644
--- a/src/net/main_test.go
+++ b/src/net/main_test.go
@@ -89,6 +89,12 @@ func setupTestData() {
 		resolveTCPAddrTests = append(resolveTCPAddrTests, resolveTCPAddrTest{"tcp6", "localhost:3", &TCPAddr{IP: IPv6loopback, Port: 3}, nil})
 		resolveUDPAddrTests = append(resolveUDPAddrTests, resolveUDPAddrTest{"udp6", "localhost:3", &UDPAddr{IP: IPv6loopback, Port: 3}, nil})
 		resolveIPAddrTests = append(resolveIPAddrTests, resolveIPAddrTest{"ip6", "localhost", &IPAddr{IP: IPv6loopback}, nil})
+
+		// Issue 20911: don't return IPv4 addresses for
+		// Resolve*Addr calls of the IPv6 unspecified address.
+		resolveTCPAddrTests = append(resolveTCPAddrTests, resolveTCPAddrTest{"tcp", "[::]:4", &TCPAddr{IP: IPv6unspecified, Port: 4}, nil})
+		resolveUDPAddrTests = append(resolveUDPAddrTests, resolveUDPAddrTest{"udp", "[::]:4", &UDPAddr{IP: IPv6unspecified, Port: 4}, nil})
+		resolveIPAddrTests = append(resolveIPAddrTests, resolveIPAddrTest{"ip", "::", &IPAddr{IP: IPv6unspecified}, nil})
 	}
 
 	ifi := loopbackInterface()
diff --git a/src/net/tcpsock.go b/src/net/tcpsock.go
index 74878fc614a6c..e957aa3005a17 100644
--- a/src/net/tcpsock.go
+++ b/src/net/tcpsock.go
@@ -77,7 +77,7 @@ func ResolveTCPAddr(network, address string) (*TCPAddr, error) {
 	if err != nil {
 		return nil, err
 	}
-	return addrs.first(isIPv4).(*TCPAddr), nil
+	return addrs.forResolve(network, address).(*TCPAddr), nil
 }
 
 // TCPConn is an implementation of the Conn interface for TCP network
diff --git a/src/net/udpsock.go b/src/net/udpsock.go
index 28b6906c5c91b..2c0f74fdabdd2 100644
--- a/src/net/udpsock.go
+++ b/src/net/udpsock.go
@@ -80,7 +80,7 @@ func ResolveUDPAddr(network, address string) (*UDPAddr, error) {
 	if err != nil {
 		return nil, err
 	}
-	return addrs.first(isIPv4).(*UDPAddr), nil
+	return addrs.forResolve(network, address).(*UDPAddr), nil
 }
 
 // UDPConn is the implementation of the Conn and PacketConn interfaces