.NET Documentation

Endpoints

This page provides an overview of how endpoints are represented and used within the System.Net.Sockets namespace in .NET.

What are Endpoints?

An endpoint represents a specific network address, including an IP address and a port number. It defines a communication point for network services. In .NET, the primary class for representing network endpoints is System.Net.EndPoint, with concrete implementations like System.Net.IPEndPoint for IP-based protocols (TCP/UDP) and System.Net.UnixDomainSocketEndPoint for Unix domain sockets.

System.Net.EndPoint Class

The abstract base class EndPoint serves as the foundation for all endpoint types. It defines common properties and methods, such as:

• AddressFamily: An enumeration that specifies the network address families supported by the System.Net classes. This typically indicates whether the endpoint uses IPv4 (InterNetwork) or IPv6 (InterNetworkV6).
• Create(SocketAddress socketAddress): Creates a new endpoint from a SocketAddress.
• Serialize(): Serializes the endpoint into a SocketAddress.

System.Net.IPEndPoint Class

IPEndPoint is the most commonly used endpoint class for IP networking. It combines an IPAddress with a port number. It inherits from EndPoint and provides specific members for IP-based communication.

Key Properties and Methods:

• IPAddress Address: Gets or sets the IP address of the endpoint.
• int Port: Gets or sets the port number of the endpoint. The port number must be between 0 and 65535, inclusive.
• Constructors: Allows creating an IPEndPoint with an IPAddress and port, or with an IPv6 address and port.
• Equals(object obj): Checks if two IPEndPoint objects represent the same endpoint.

Example: Creating and Using an IPEndPoint

using System;
using System.Net;

public class EndPointExample
{
    public static void Main(string[] args)
    {
        // Create an IPEndPoint for an IPv4 address and port
        IPAddress ipAddress = IPAddress.Parse("192.168.1.100");
        int port = 8080;
        IPEndPoint endPoint = new IPEndPoint(ipAddress, port);

        Console.WriteLine($"Endpoint created: {endPoint.ToString()}");
        Console.WriteLine($"Address Family: {endPoint.AddressFamily}");
        Console.WriteLine($"IP Address: {endPoint.Address}");
        Console.WriteLine($"Port: {endPoint.Port}");

        // Example with IPv6
        IPAddress ipv6Address = IPAddress.Parse("2001:db8::1");
        int ipv6Port = 12345;
        IPEndPoint ipv6EndPoint = new IPEndPoint(ipv6Address, ipv6Port);
        Console.WriteLine($"IPv6 Endpoint: {ipv6EndPoint.ToString()}");

        // Creating from a string
        try
        {
            EndPoint anotherEndPoint = EndPoint.Parse("10.0.0.1:9000");
            Console.WriteLine($"Parsed endpoint: {anotherEndPoint.ToString()}");
        }
        catch (FormatException e)
        {
            Console.WriteLine($"Error parsing endpoint: {e.Message}");
        }
    }
}
            

System.Net.UnixDomainSocketEndPoint Class

For scenarios involving Unix-domain sockets (primarily on Linux and macOS), UnixDomainSocketEndPoint represents an endpoint using a file system path.

• Constructor: Takes a file system path as a string.
• NodeName: Gets the file system path associated with the endpoint.

This class is crucial for inter-process communication on Unix-like systems using sockets.

Serialization and Deserialization

The Serialize() and Create() methods on the EndPoint class are fundamental for converting between the abstract EndPoint representation and the lower-level, protocol-specific SocketAddress structure. This is often handled implicitly by socket classes but can be useful for advanced scenarios.