AT&T U120 User manual

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AT&T U120 Install Guide
Version D6.0.1

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Table of Contents
Installing the U120.........................................................................................................................................................................................5
Step 1: Establish Connectivity to the Internet.............................................................................................................................................5
Option a. Wired Ethernet Connection.....................................................................................................................................................5
Option b. Cellular Connection................................................................................................................................................................5
Option c. WiFi Connection.....................................................................................................................................................................6
Step 2: Establish Local Network Connectivity ............................................................................................................................................7
Option a. Wired LAN Connection..........................................................................................................................................................7
Option b. WiFi LAN Connection............................................................................................................................................................7
Configuring the U120 Internet Connectivity...............................................................................................................................................8
Access the U120 Web Interface...................................................................................................................................................................8
Primary IPv4 WAN Interface Setup ............................................................................................................................................................9
Configuring DHCP ...............................................................................................................................................................................10
Configuring a Static IP Address............................................................................................................................................................11
Configuring IP Unnumbered.................................................................................................................................................................12
Configuring PPPoE...............................................................................................................................................................................13
Configuring a Cellular Connection.......................................................................................................................................................14
Cellular service verification..................................................................................................................................................................16
WiFi WAN Interface.............................................................................................................................................................................17
Administrator Access.................................................................................................................................................................................20
Establishing VPN Connectivity .................................................................................................................................................................21
Firewall Ports ...........................................................................................................................................................................................24
LAN Port Configuration.............................................................................................................................................................................24
VLANS.......................................................................................................................................................................................................24
WiFi on Local LAN..............................................................................................................................................................................28
AT&T U120 Hardware / Signal Overview ................................................................................................................................................29
Front Panel Indicators, Switches & Slots .................................................................................................................................................29
Special Cases ............................................................................................................................................................................................29
Rear Panel Ports & Connectors................................................................................................................................................................30
Right Side Expansion Slot .........................................................................................................................................................................30

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Installing the U120
Unpack the U120, the cables, antennas, and the power supply. Connect the antennas and power supply. Make sure the
power switch is in the on position.
Note: In certain regions, antennas and the cellular modem are not included.
Installation steps vary depending on type of Internet connection and type of local network connectivity. See Figure 1: U120
Rear Panel for connectors on the rear panel of the U120.
Figure 1: U120 Rear Panel
Follow the guide below to determine the necessary setup steps for your environment.
Step 1: Establish Connectivity to the Internet
In many cases, a wired Ethernet connection will be provided by your ISP. This type of connection includes DSL, Cable and
Managed Internet Connections. It is also possible to connect to the Internet via high-speed cellular access, in which case
you should proceed to the Configuring a Cellular Connection section in this guide. It is also possible to connect to the
Internet via WiFi, in which case you should proceed to the WiFi WAN Interface
Once an Internet Connection has been established, the U120 will try to retrieve its configuration from the network, and if
successful, may perform an automatic reboot to pick up the new configuration. This should occur within the first 2-3 minutes
after initial power on. Wait for a steady GREEN ONLINE light on the front panel to indicate the U120 is ready for use.
Basic connectivity has devices on the local network connected to the LAN ports on the back of the U120. The broadband
connection is usually established via the WAN1 Ethernet port.
Option a. Wired Ethernet Connection
Use an Ethernet cable to connect your Internet broadband interface device to the Ethernet port labeled WAN1 on the U120.
The U120 should be connected directly to the broadband interface device. The black cable provided inside the U120’s
packing box is an Ethernet cable.
Dynamic Host Control Protocol (DHCP) is the default configuration for Internet IP addressing of the U120 Internet network
interface. If your device automatically obtains an address from your ISP through DHCP, it should auto-configure shortly
after powering up.
If your Broadband Internet Service Provider supplied you with a static IP address or PPPoE account information for use with
your broadband connection, you will need to perform additional configuration of the primary interface through the U120 web
interface in order to establish Internet access and to retrieve the device configuration. See “Configuring a Static IP
Address” or “Configuring PPPoE” later in the guide.
Option b. Cellular Connection
Certain U120's will have an imbedded cell card and SIM already installed. If the device has an imbedded call card and SIM,

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please work with your AT&T account team to activate the SIM.
The U120 needs basic setup of the cellular modem via the web interface before it can connect to the Internet to retrieve its
configuration. See “Configuring a Cellular Connection”later in the guide. After a cellular connection is set up and
connected the GREEN ONLINE light on the front panel will blink to indicate the U120 is using a cellular connection.
Option c. WiFi Connection
The U120's also can use a WiFi connection for connectivity to the Internet. The U120 needs basic setup of the WiFi
connection before it can connect to the Internet to retrieve its configuration. See WiFi WAN Interface later in this guide
for details.

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Step 2: Establish Local Network Connectivity
In most cases, your devices will attach directly to the U120 via one of the 8 LAN ports with an Ethernet cable. The LAN
configuration of the U120 is controlled by your IS Department and is not configurable by any user.
Option a. Wired LAN Connection
The default configuration for computers attaching to any of the U120 Local LAN ports is DHCP. If you are not sure if you
are using DHCP for your LAN IP addressing, please contact your Information Services (IS) Department for assistance before
proceeding.
If your computer is configured to use DHCP, but the U120 is not providing your computer with an IP address, please contact
your IS Department. In this case you will not be able to access the web Interface as described below.
Note: After the U120 has retrieved its configuration, the local LAN addresses are likely to change from the default values.
If the IP addressing does change, it may be necessary to reboot or reconfigure your devices attached to the U120 in order
to obtain/assign a valid IP address to use when accessing the Local LAN ports of the U120.
Option b. WiFi LAN Connection
Instead of using a physical connection for devices connecting to the LAN the U120 can also be configured to use WiFi. See
WiFi on Local LAN later in the guide for details.
The default configuration for computers attaching to any of the U120 Local LAN ports is DHCP. If you are not sure if you
are using DHCP for your LAN IP addressing, please contact your Information Services (IS) Department for assistance before
proceeding.
If your computer is configured to use DHCP, but the U120 is not providing your computer with an IP address, please contact
your IS Department. In this case you will not be able to access the web Interface as described below.
Note: After the U120 has retrieved its configuration, the local LAN addresses are likely to change from the default values.
If the IP addressing does change, it may be necessary to reboot or reconfigure your devices attached to the U120 in order
to obtain/assign a valid IP address to use when accessing the Local LAN ports of the U120.

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Configuring the U120 Internet Connectivity
In most cases, no user-level configuration is required to set up the WAN connection as an IP address is retrieved
automatically through DHCP and the device configuration is retrieved from the network. In some cases, it is necessary to
perform some initial configuration through the web Interface –for example, if the primary Internet connection needs to be
manually configured prior to use. To do this it will be necessary to access the U120 web interface.
Access the U120 Web Interface
The U120 web interface can be accessed from a computer attached to a LAN port. The web interface can be used to access
various administration functions and can allow the VPN connection to be controlled.
1. Open your web browser.
2. In the Address or Location box enter http://attvpngateway.att.com and press the Enter key.
3. This will take you to one of several possible initial pages, depending on your configuration and connectivity
options. A menu will appear on the left side of each page for access to sections such as “Home”, “Network
Settings”, and “Help”
If the U120 has already retrieved its configuration, it may have been configured for Administrator access. See Administrator
Access later in the guide for more information on gaining administrator access to the web interface.

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Primary IPv4 WAN Interface Setup
To configure the primary interface for something other than DHCP (or to change DHCP settings), follow these steps:
1. Access the web interface as described on page 8.
2. Click the entry for Network Settings to display the Network Settings sub-menu and click the entry for WAN Setup
as shown in Figure 2: Network Settings Selection.
Figure 2: Network Settings Selection

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Configuring DHCP
To configure DHCP, follow these steps after reaching Figure 3: DHCP Settings
1. Select “DHCP” from the choices that are displayed.
2. Check the checkboxes for the DHCP options required by your ISP in Figure 3: DHCP Settings. Most ISPs do
NOT require any of these checkboxes to be set. If needed, populate the VLAN fields as defined by your ISP. Most
ISPs do NOT require VLAN information to be specified. Therefore, unless you have special circumstances you
should be able to just skip to the next step.
3. Press Submit to display a confirmation dialog where you can review the new WAN setup.
4. Press Confirm to initiate a reboot to pick up the new configuration. After reboot, skip to the section titled
“Establishing VPN Connectivity”on page 21.
Figure 3: DHCP Settings