### **Network**

#### **IPv6**

*   [alpha] IPv6 support has been added. Notable IPv6 support details include:
    *   Support for IPv6-only Kubernetes cluster deployments. **<span style="text-decoration:underline;">Note:</span>** This feature does not provide dual-stack support.
    *   Support for IPv6 Kubernetes control and data planes.
    *   Support for Kubernetes IPv6 cluster deployments using kubeadm.

type restError string

func (e restError) Error() string {
	return string(e)
}

func (e restError) Timeout() bool {
	return true
}

// Given a string of the form "host", "host:port", or "[ipv6::address]:port",
// return true if the string includes a port.
func hasPort(s string) bool { return strings.LastIndex(s, ":") > strings.LastIndex(s, "]") }

// removeEmptyPort strips the empty port in ":port" to ""

 * authentication.
 *
 * ### Host
 *
 * The host identifies the webserver that serves the URL's resource. It is either a hostname like
 * `square.com` or `localhost`, an IPv4 address like `192.168.0.1`, or an IPv6 address like `::1`.
 *
 * Usually a webserver is reachable with multiple identifiers: its IP addresses, registered
 * domain names, and even `localhost` when connecting from the server itself. Each of a web server's

				proxyLogIf(GlobalContext, err)
			}
		},
	})

	// On macOS, if a process already listens on LOCALIPADDR:PORT, net.Listen() falls back
	// to IPv6 address ie minio will start listening on IPv6 address whereas another
	// (non-)minio process is listening on IPv4 of given port.
	// To avoid this error situation we check for port availability.

    * DualStack:
    * => IPv4 BackendPool name == clusterName
    * => IPv6 BackendPool name == <clusterName>-IPv6
    * This result into:
    * - clusters moving from IPv4 to duakstack will require no changes

  }

  @Test fun verifyAsIpAddress() {
    // IPv4
    assertThat("127.0.0.1".canParseAsIpAddress()).isTrue()
    assertThat("1.2.3.4".canParseAsIpAddress()).isTrue()

    // IPv6
    assertThat("::1".canParseAsIpAddress()).isTrue()
    assertThat("2001:db8::1".canParseAsIpAddress()).isTrue()
    assertThat("::192.168.0.1".canParseAsIpAddress()).isTrue()

- Upgrade node local dns to 1.17.0 for better IPv6 support ([#99749](https://github.com/kubernetes/kubernetes/pull/99749), [@pacoxu](https://github.com/pacoxu)) [SIG Cloud Provider and Network]

### IPv4/IPv6 run

 *  Fix: Recover gracefully when a coalesced connection immediately goes unhealthy.
 *  Fix: Defer the `SecurityException` when looking up the default proxy selector.
 *  Fix: Don't use brackets formatting IPv6 host names in MockWebServer.
 *  Fix: Don't permit cache iterators to remove entries that are being written.


## Version 4.0.1

_2019-07-10_

    // IPv6 colons don't interfere with port numbers or passwords.
    assertThat(parse("http://[::1]:8080/").port).isEqualTo(8080)
    assertThat(parse("http://user:password@[::1]/").password).isEqualTo("password")
    assertThat(parse("http://user:password@[::1]:8080/").host).isEqualTo("::1")

    // Permit the contents of IPv6 addresses to be percent-encoded...