InetAddress Class

Definition

[Android.Runtime.Register("java/net/InetAddress", DoNotGenerateAcw=true)]
public class InetAddress : Java.Lang.Object, IDisposable, Java.Interop.IJavaPeerable, Java.IO.ISerializable

[<Android.Runtime.Register("java/net/InetAddress", DoNotGenerateAcw=true)>]
type InetAddress = class
    inherit Object
    interface ISerializable
    interface IJavaObject
    interface IDisposable
    interface IJavaPeerable

Inheritance

Object

Object

InetAddress

Derived

Java.Net.Inet4Address

Java.Net.Inet6Address

Attributes

RegisterAttribute

Implements

IJavaObject IJavaPeerable ISerializable IDisposable

Remarks

This class represents an Internet Protocol (IP) address.

An IP address is either a 32-bit or 128-bit unsigned number used by IP, a lower-level protocol on which protocols like UDP and TCP are built. The IP address architecture is defined by RFC 790: Assigned Numbershttp://www.ietf.org/rfc/rfc790.txt, RFC 1918: Address Allocation for Private Internetshttp://www.ietf.org/rfc/rfc1918.txt, RFC 2365: Administratively Scoped IP Multicasthttp://www.ietf.org/rfc/rfc2365.txt, and RFC 2373: IP Version 6 Addressing Architecturehttp://www.ietf.org/rfc/rfc2373.txt. An instance of an InetAddress consists of an IP address and possibly its corresponding host name (depending on whether it is constructed with a host name or whether it has already done reverse host name resolution).

<h3> Address types </h3>

<blockquote><table cellspacing=2 summary="Description of unicast and multicast address types"> <tr><th valign=top>unicast</th> <td>An identifier for a single interface. A packet sent to a unicast address is delivered to the interface identified by that address.

The Unspecified Address -- Also called anylocal or wildcard address. It must never be assigned to any node. It indicates the absence of an address. One example of its use is as the target of bind, which allows a server to accept a client connection on any interface, in case the server host has multiple interfaces.

The unspecified address must not be used as the destination address of an IP packet.

The Loopback Addresses -- This is the address assigned to the loopback interface. Anything sent to this IP address loops around and becomes IP input on the local host. This address is often used when testing a client.</td></tr> <tr><th valign=top>multicast</th> <td>An identifier for a set of interfaces (typically belonging to different nodes). A packet sent to a multicast address is delivered to all interfaces identified by that address.</td></tr> </table></blockquote>

<h4> IP address scope </h4>

Link-local addresses are designed to be used for addressing on a single link for purposes such as auto-address configuration, neighbor discovery, or when no routers are present.

Site-local addresses are designed to be used for addressing inside of a site without the need for a global prefix.

Global addresses are unique across the internet.

<h4> Textual representation of IP addresses </h4>

The textual representation of an IP address is address family specific.

For IPv4 address format, please refer to Inet4Address#format; For IPv6 address format, please refer to Inet6Address#format.

There is a couple of System Properties affecting how IPv4 and IPv6 addresses are used.

<h4> Host Name Resolution </h4>

Host name-to-IP address resolution is accomplished through the use of a combination of local machine configuration information and network naming services such as the Domain Name System (DNS) and Network Information Service(NIS). The particular naming services(s) being used is by default the local machine configured one. For any host name, its corresponding IP address is returned.

Reverse name resolution means that for any IP address, the host associated with the IP address is returned.

The InetAddress class provides methods to resolve host names to their IP addresses and vice versa.

<h4> InetAddress Caching </h4>

The InetAddress class has a cache to store successful as well as unsuccessful host name resolutions.

By default, when a security manager is installed, in order to protect against DNS spoofing attacks, the result of positive host name resolutions are cached forever. When a security manager is not installed, the default behavior is to cache entries for a finite (implementation dependent) period of time. The result of unsuccessful host name resolution is cached for a very short period of time (10 seconds) to improve performance.

If the default behavior is not desired, then a Java security property can be set to a different Time-to-live (TTL) value for positive caching. Likewise, a system admin can configure a different negative caching TTL value when needed.

Two Java security properties control the TTL values used for positive and negative host name resolution caching:

<blockquote> <dl> <dt><b>networkaddress.cache.ttl</b></dt> <dd>Indicates the caching policy for successful name lookups from the name service. The value is specified as as integer to indicate the number of seconds to cache the successful lookup. The default setting is to cache for an implementation specific period of time.

A value of -1 indicates "cache forever". </dd> <dt><b>networkaddress.cache.negative.ttl</b> (default: 10)</dt> <dd>Indicates the caching policy for un-successful name lookups from the name service. The value is specified as as integer to indicate the number of seconds to cache the failure for un-successful lookups.

A value of 0 indicates "never cache". A value of -1 indicates "cache forever". </dd> </dl> </blockquote>

Added in JDK1.0.

Java documentation for java.net.InetAddress.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to