The invention relates to performing server initiated database synchronisation between a mail server 10 and a client on a mobile computing device 70. Both the mail server and the client are provided with a copy of a user mailbox 40, 40A. When a message for that user is received at the mail server, this is stored in their server mailbox. The mail server then initiates a link with the client and prompts it to dial into the mail server in order to synchronise its local copy of the mailbox with the server copy. In this manner new mail is automatically transferred to the client device upon receipt at the mail server.