MailSwitch automatically switches your outgoing mail server based on your IP address. It is designed for users that regularly connect to two or more service providers and have to manually change their outgoing mail server when changing networks. You can add 20 associations of mail servers and IP address ranges.
MailSwitch compares your IP address and makes sure your outgoing mail server is correct for the network you are connected to. MailSwitch is designed to stay in your system tray with a simple context menu to change settings or update the mail server.