C# IPv4/IPv6 agnostic socket listener

I'm trying to to figure out how to create a protocol agnostic socket listener in C# - it should grab IPv4 and IPv6 requests. Everything I can find on Google seems to be C. Attempting something similar to what I saw for C, I tried the following code: ``` /*Socket*/ m_sock = null; /*IPAddress*/ m_addr = null; /*int*/ m_port = port; /*port passed to function*/ /*int*/ m_listenqueue = listen_queue_size; /*also passed to function, number of pending requests to allow before busy*/ IPAddress[] addrs = Dns.GetHostEntry("localhost").AddressList; if(family == null) m_addr = addrs[0]; else { foreach(IPAddress ia in addrs) { if(ia.AddressFamily == family) /*desired address family also passed as an argument*/ { m_addr = ia; break; } } } if(m_addr == null) throw new Exception(this.GetType().ToString() + ".@CONSTRUCTOR@: Listener Initailization Error, couldn't get a host entry for 'localhost' with an address family of " + family.ToString()); m_sock = new Socket(m_addr.AddressFamily, SocketType.Stream, ProtocolType.IP); /*START "AGNOSTICATION LOGIC"... Tried here...*/ if(m_addr.AddressFamily == AddressFamily.InterNetworkV6) //allow IP4 compatibility { m_sock.SetSocketOption(SocketOptionLevel.Tcp, SocketOptionName.AcceptConnection, true); /*fails*/ m_sock.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AcceptConnection, true); /*fails*/ m_sock.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.AcceptConnection, true); } /*END "AGNOSTICATION LOGIC" */ IPEndPoint _endpoint = new IPEndPoint(m_addr, m_port); m_sock.Bind(_endpoint); /*... tried here*/ m_sock.Listen(m_listenqueue); /*... and tried here*/ ``` I've tried the logic at the three places marked, and regardless of where I put it, the two listed lines will throw an invalid argument exception. Can anyone recommend to me how I should make a socket that will listen to both IPv4/IPv6?