Datagrams from Java
Posted on 1998-03-15
Hello there, wonder if anyone can help me.
I am trying to send and receive datagrams using Java. I have copied two programs from a book, one to receive datagrams and one to send.
The receive datagram program has a parameter of a port to receive the data on.
The send program has three parameters, host , port and message.
I have a dial up account.
Now, the programs have all compiled correctly but if I try and use the send program using my node name I get the message "Network is unreachable", if I use it with a node that I know exists "post.demon.co.uk" the datagram is sent (I presume it is as the modem lights flash!!), so this must mean the the DNS is working...
If I try it with my IP address, I get the same message.
If I try it with 127.0.0.1 (loopback) the send light flashes once, but I do not receive the message.
Basically my question is, what ports should I be specifying with modem dial up and what is going on with the DNS ?
Can anybody help me ?