I guess you read data via RS232 from a device and you want to make this data available over network to other applications.
So you want to carry this data via TCP/IP to one or more clients.
You need something to read the data from the serialport stream and copy it into the socket stream.
Take a look at
SerialPort Class[
^]
TcpClient Class[
^]
BTW: AFAIK RS232 desribes the physical layer
RS 232[
^]
Even if both P in TCP/IP stand for protocol you can use this protocols to carry another protocol, e.g. http. TCP/IP is suitable for all kind of point to point communication in a IP based network.