Question

I am learning how to use the boost asio libraries and I am using the UDP examples on visual studio 2008. I have compiled and run the server application(name udp_server.exe). I have tried to run the client application but is does connect to the server. How do I specify the host and service name to the application for it to connect. I have specified the machine name but I get an error “No connection could be made because the target machine actively refused it”. Are there some prerequisite setup I need to perform on my Windows 7 machine to get the examples to work?

Answer 1

Assuming that you are referring to the “Daytime.4 – A synchronous UDP daytime client” example, the server’s host name is passed as argv[1] (the first command-line parameter) to the udp::resolver::query ctor. As you can see from the docs, the port is passed as the 3rd parameter to the ctor. This parameter can be a string representation of the port number or a “service name”. Quoting the docs about this:

On POSIX systems, service names are
typically defined in the file
/etc/services. On Windows, service
names may be found in the file
c:\windows\system32\drivers\etc\services.

If all this seems ok and connection still fails, check the firewall settings on the server to make sure that it allows connections on the chosen port.