IPv6:侦听连接时，"::"是否等同于"0.0.0.0"? [英] IPv6: Is `::' equivalent to `0.0.0.0' when listening for connections?

问题描述

当我检查 IPGlobalProperties.GetActiveTcpListeners() ，我在0.0.0.0和::上看到了侦听器.

我相信在0.0.0.0上的端口上侦听等同于在任何网络适配器上的端口上侦听，至少我对Windows套接字API的记忆如此.

对我来说，::表示IPv6的等效含义，因此[::]:49156上的侦听器将侦听所有IPv6网络适配器上的端口49156，其中[::1]:1434将是端口仅在IPv6回送适配器上.

这正确吗?

我假设IPv6侦听端点仅适用于IPv6适配器.也就是说，如果适配器仅具有IPv4地址，则[::]:49156上的侦听器将不会接收与端口49156的连接?

还有，没有人注意到GetActiveTcpListeners()的MSDN文章错误地声明返回的对象在所有TCP状态中包括侦听器，除了 侦听状态"?

解决方案

我相信在0.0.0.0上的端口上侦听等同于在任何网络适配器上的端口上侦听，至少我对Windows套接字API的记忆如此.

那是正确的. 0.0.0.0定义为INADDR_ANY，可用于侦听所有本地IPv4适配器.

对我来说，::表示IPv6的等效含义，因此:::49156上的侦听器将侦听所有IPv6网络适配器上的端口49156，其中::1:1434将是端口1434仅IPv6回送适配器.

从聆听的角度来看，是的. ::定义为INADDR6_ANY，可用于侦听所有本地IPv6适配器. ::1定义为INADDR6_LOOPBACK.

我假设IPv6侦听端点仅适用于IPv6适配器.也就是说，如果适配器仅具有IPv4地址，则:::49156上的侦听器将不会接收与端口49156的连接?

这取决于听众.仅IPv6的侦听器无法在IPv4适配器上侦听，也不能接受IPv4客户端.但是，双栈侦听器绑定到可以绑定到IPv4和IPv6适配器并接受IPv4和IPv6客户端，其中accept()，WSAAccept()和getpeername()将IPv4地址报告为IPGlobalProperties.GetActiveTcpListeners(), I see listeners on 0.0.0.0 as well as ::.

I believe that listening on a port on 0.0.0.0 is equivalent to listening on a port on any network adapter, at least my memory of the Windows socket API says that this is so.

It also makes sense to me that :: would mean the equivalent in IPv6 parlance so a listener on [::]:49156 would be listening to port 49156 on all IPv6 network adapters where as [::1]:1434 would be port 1434 on only the IPv6 loopback adapter.

Is this correct?

I assume that IPv6 listen end-points only apply to IPv6 adapters. That is, if an adapter only had an IPv4 address, connections to it port 49156 would not be received by a listener on [::]:49156?

Also, has anyone noticed that the MSDN article for GetActiveTcpListeners() incorrectly declares that the returned objects "include listeners in all TCP states except the Listen state."?

解决方案

I believe that listening on a port on 0.0.0.0 is equivalent to listening on a port on any network adapter, at least my memory of the Windows socket API says that this is so.

That is correct. 0.0.0.0 is defined as INADDR_ANY and can be used to listen on all local IPv4 adapters.

It also makes sense to me that :: would mean the equivalent in IPv6 parlance so a listener on :::49156 would be listening to port 49156 on all IPv6 network adapters where as ::1:1434 would be port 1434 on only the IPv6 loopback adapter.

From the perspective of listening, yes. :: is defined as INADDR6_ANY and can be used to listen on all local IPv6 adapters. ::1 is defined as INADDR6_LOOPBACK.

I assume that IPv6 listen end-points only apply to IPv6 adapters. That is, if an adapter only had an IPv4 address, connections to it port 49156 would not be received by a listener on :::49156?

That depends on the listener. An IPv6-only listener cannot listen on an IPv4 adapter and cannot accept IPv4 clients. However, a dual-stack listener bound to INADDR6_ANY can bind to IPv4 and IPv6 adapters and accept both IPv4 and IPv6 clients, where IPv4 addresses are reported by accept(), WSAAccept(), and getpeername() as IPv4-mapped IPv6 addresses.

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