>>The AS/400 service that I am using needs the first 5 characters to denote the length of
>>the command string (including the 5 character command length prefix) that I am passing
>>and I wasn't prefixing my command with that information, so the AS/400 service was
>>silently choking.

I know what you mean. I've passed many invalid bytes to a "server" and choked it. IMHO, the server should not allow a sloppy request, and should tell you so. The server should not fail if given a bad request.

>>When would I need to use the bind method?

In general, one uses the .Bind method, followed by the .Listen method if you want your socket to accept connections.

>>How can I get the IP address of machine running the program if I do want to bind?

If connected via sockets, you already have the IP and port. I'm not sure if I understand the question.

>>Should I set any of the SocketOptions? Currently, I am setting >>SocketOptionName.SendTimeout and SocketOptionName.ReceiveTimeout. Do I need to, or are >>the .NET defaults reasonable values?

I've accepted the defaults.