This article explains how to create a serial Modem (PPP) interface on the Sophos UTM.
This article focuses on a single interface type. To learn more about other interface types, please view KB article 118899.
Known to apply to the following Sophos product(s) and version(s) Sophos UTM
Interfaces may be added and edited in the WebAdmin interface under: Interfaces & Routing | Interfaces | Interfaces.
Line Speed: The default value is normally correct, although some older modems may require a slower serial port connection speed.
Flow Control: This should be left at Hardware, unless the serial device does not support it.
INIT String: If necessary, additional or alternate modem commands may be supplied for initializing the modem before dialing.
Reset String: If necessary, additional or alternate modem commands may be supplied for initializing the modem when disconnecting.
MTU: Dial-UP RAS servers typically use an MTU of 576. Setting the value to 576 may improve performance for this connection type.
Displayed max: (Optional) The displayed max value is a numeric field that is used for display purposes only. Entering the correct value in this field to match the available bandwidth provided on this link, allows the UTM to show accurate percentage graphs for each interface on dashboard. This has no impact on network behavior, as it is only used for display purposes.
Every comment submitted here is read (by a human) but we do not reply to specific technical questions. If you need technical support please post a question to our community. Alternatively for licensed products open a support ticket.