MySQL has gone away

[TEKNE informatica & comunicazione]

Do you know if there is a relationship between the socket timeout and the
connection to a MySQL server with the revOpenDatabase function?
When I am connected to a remote server machine and I don't send a query for
more than 5 minutes, I obtain the error  "MySQL has gone away".
PS
I have tuned the server system variables in order to have a good connection
(wait_timeout, max_allowad_packets, etc.).
If I make the connection from the LAN I don't have this error!

Thank you for your suggestions.

Riccardo