CODEWITHSUNDEEP
c#network-programming
sarat
sarat

Reputation: 11140

What's the difference between IPAddress.Any and IPAddress.IPv6Any fields?

I tried the following code to make my code work in dual stack mode. Unfortunately, it's not opening port in the dual stack mode. 

var listener = new TcpListener(IPAddress.Any, 2222);
listener.Server.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, 0);
listener.Start();

Later I realized that changing to var listener = new TcpListener(IPAddress.IPv6Any, 2222); would make it work for me. What exactly is the difference between

IPAddress.Any and IPAddress.IPv6Any fields?

The documentation on MSDN is a bit vague

Upvotes: 7

Views: 14385

Answers (2)

Edward Brey
Edward Brey

Reputation: 41718

To listen on both the IPv4 and IPv6 stacks, use this code:

var listener = new TcpListener(IPAddress.IPv6Any, 2222);
listener.Server.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, false);

IPv6Any tells Windows to listen on the IPv6 stack. Setting the socket option to false tells Windows to not limit itself to the IPv6 stack, but rather to also listen on the IPv4 stack. The default is to only listen on the stack explicitly specified.

Upvotes: 7

PhonicUK
PhonicUK

Reputation: 13864

IPAddress.Any is for all IPv4 interfaces, IPAddress.IPv6Any is for all IPv6 interfaces.

IPAddress.Any is 0.0.0.0, IPAddress.IPv6Any is ::

If you just use IPv6Any without using SocketOptionName.IPv6Only then you can accept both IPv4 and IPv6 connections on the same socket.

Upvotes: 12

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