At the present time MSP is not officially supported over dial-up connections. Since MSP is designed to work over an IP-based connection, there is likely no fundamental reason why it could not work, given that the connection was configured and established by the time MSP tried to connect.  But no testing or certification of MSP over such a connection has been done, hence we can make no claims that unusual or undesirable will not occur.  Since it is not officially supported, any such deployment would be "use at your own risk".  If problems were encountered, we cannot promise a timely solution. Even if you were able to get it to work, there likely will be logistical challenges.  You would need to configure the modem connection.  You would need to connect and disconnect the dial-up connection and ensure that the connection is available when MSP needs it.  There may also be issues with mobile device termination that may affect the ability to perform Remote Control over such a connection. We have had dial-up support on the MSP feature wish-list for a long time, but there has not been a sufficient demand to raise this feature in priority relative to other requested features.  As a result, it has not yet been scheduled into a specific MSP release.  If and when this is made a part of MSP, we will need to have enough information about the use cases to be able to fully define the feature and it's requirements sufficiently to allow us to ensure that our implementation satisfies as many customers as possible.  If you have a need for this feature, please file a GRIP and include as many details as possible.