Creating a 3G/UMTS interface on the Sophos UTM

  • Article ID: 119010
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  • Updated: 27 Jul 2015

This article explains how to create a 3G/UMTS interface on the Sophos UTM. 

Supported USB Cellular modem devices may be connected to a USB port on the UTM, and used as an internet connection. 

Typical Uses:

  • Due to bandwidth costs, 3G/UMTS interfaces are typically used as a backup/standby internet connection.
  • 3G/UMTS connections are frequently used in regions prone to storms, where periodic loss of wired internet connections may be more likely than in most areas.

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 Manager
Sophos UTM

What To Do

  1. Connect the USB cellular modem to an open USB port on the UTM. 
  2. Reboot the UTM. This will allow the device to be detected and made available for configuration. 

Interfaces may be added and edited in the WebAdmin interface under: Interfaces & Routing | Interfaces | Interfaces.

  1. Click the New Interface button to add a new interface.
  2. Then in the Type field, select: 3G/UMTS
  3. The following image and table outline the options available and how to fill them out:
Interface Image Configuration Options

Name: This is the name that will be shown throughout the UTM configuration, wherever this interface is referenced. Names that indicate, or are specific to, purpose, are often the most useful. For example names like: Internal, DMZ, Guest, External. or External-XO, External-ATT, are purpose-specific names that make it clear to someone who didn't create the object, what purpose it serves.

Hardware: Detected available and compatible USB Cellular devices are listed here. If none are listed, either the UTM must be rebooted in order for the device to be detected, or the device is not compatible. 

IPv4 Default GW: If the interface is a connection to the internet, then a default gateway IP may be set by enabling this option. If this is not an internet connection, then this option does not normally need to be enabled.

PIN: If required an ISP provided PIN may be entered in this field. This is normally not needed, and if unsure, leave this blank. 

APN Autoselect: The APN value is normally stored in the connected device. APN Autoselect will retrieve and use the stored APN value. If using a device not issued by the cellular carrier, it may be necessary to de-select this option, and enter the correct APN value in the APN field offered. The correct APN value must be provided by the carrier.

Username: The internet provider will provide credentials to use when connecting to their service. The supplied username should be entered here.

Password: The internet provider will provide credentials to use when connecting to their service. The supplied password should be entered here.

Dial String: Normally, the correct dial string will be provied by default. If the provided dial string is incorrect, the correct value must be provided by the carrier.

Comment: (Optional) This is a free text field, where brief comments may be recorded

Advanced Options

INIT String: If necessary, additional or alternate dial commands may be supplied for initializing the modem before dialing

Reset String: If necessary, additional or alternate control 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.



If you need more information or guidance, then please contact technical support.

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