How exactly a program in windows determines if a TCP/IP connection is available?

[quincer]

Hiya guys
I was wondering how exactly a program determines if a Internet Connection is available?
I was having some problems before when using PPPoE which I found out v1.4+ of EnterNet resolved.
But curious as to if you were on a dial up, is there something in the registr that tells the computer there is an active connection?


Thanks!

 

[Mark R]

There are functions in Windows that allow a program to determine if, and which dial-up connection is available. For example, a program could use the RasEnumConnections() function which obtains the names/telephone numbers of all the currently active dial-up connections.

Such a system is not available for ethernet or other connection method. Typically programs ask at install time if they use dial-up or other methods of connection. If the user selects other, then the program just assumes that the connection is full-time - if the connection isn't full time then it must be able to handle the errors that will occur, if it tries to connect without a connection being available.