AT&T Uverse Internet with 5 Static IP and 3rd Party Router

Recently, I decided we were paying too much for our small business internet.  Our current provider provides good service, but we aren’t in a field that demands 100% up time so I felt that I could shop around for something a bit less expensive, even if it meant losing a bit of speed in the process.

We have three locations, one large HQ and two satellite campuses.  The HQ currently uses 35/5 service from TWBC but if I watch the traffic on our router, very little of the bandwidth is actually utilized most of the time.  I assumed then, that I could shop around a little bit for a few other options even if it meant losing some bandwidth.  Well, that brought me to AT&T Uverse “Business” internet which is really just a re-branded residential service with less restrictions.  In total, including the 5 static IPs, they could offer 18/2 service for roughly 1/3 of the cost.  Given the possible savings there, I decided I had to give it a shot.

Just getting the gateway installed at our location was a pain.  It wasn’t configured properly, the technicians didn’t communicate with each other well (several attempts to draw lines from the CO ended in conflicting setups) and support was woefully unequipped to answer questions for a business trying to route traffic through their own router. I also had to call in order to get the IP address information.

After all the back and forth, I finally was able to get this running but I was so frustrated during setup just trying to find accurate instructions, I figured I’d post what worked for me, here.

Our equipment:

  • Cisco 891 Integrated Security Router
  • Motorola NVG859 (AT&T)
  • 5 static (really 8) public IP addresses.

AT&T support repeatedly had me attempt to set “IP Passthrough” to “DHCP Fixed” and other settings but this resulted in requiring the CISCO interfaces setup for DHCP and in the gateway handing out yet another public IP address to the outside world.  Since we host our own e-mail server and we secure several web applications based on what the client IP is, this wouldn’t work, especially if this other IP (not one of the 5 we were given) was handed out dynamically.

Here is what worked:

The Cisco router’s interface that is connected to the NVG589 was set to a manual IP address that was provided by AT&T.

Setup your Cisco router and plug the inside interface into the NVG589.

  1. Plug into your NVG or connect to the wifi if tech support enabled it.
  2. By default, the IP address of the unit will be, if this is the same network as your business network, you’ll need to disconnect from that network first.
  3. Once connected, click on “Home Network” and within that, “Subnets & DHCP”
    1. The password for this page should be written on your gateway.
  4. Under the “Private LAN Subnet” change the IPv4, subnet mask and the DHCP address information to values that will not conflict with your work network or any networks that it may be connected to.
  5. Under “Public Subnet”:
    1. Set “Public Subnet Enable” to “ON”
    2. Set “Public IPv4 Address to the gateway address that AT&T gave you.  If AT&T handed you a /29 address, this will typically be the last address in that group.
    3. Set the “Public Subnet Mask” to what AT&T gave you.  For a 5 block, this is
    4. Set “DHCPv4 Start Address” to the first routable IP AT&T provided.
    5. Set “DHCPv4 End Address” to the last routable IP AT&T provided.
    6. Set “Allow Inbound Traffic” to “ON”
    7. Set “Primary DHCP Pool” to “Private”.
  6. Leave all other settings on this page off.
  7. Click Save at the bottom of the page.  Don’t reboot if asked.
  8. Click on “Firewall” at the top of the page and within that, click on “IP Passthrough”.
    1. Set “Allocation Mode” to “Default Server”
      1. Under “Default Server Internal Address” you should see only the Cisco 891 manually set IP and possibly whatever laptop you connected to the device.  Select the Cisco device (which should be one of your public addresses).  This may only work for a single device.
    2. Alternatively, set “Allocation Mode” to “Passthrough” and set “Passthrough Mode” to “Manual”.
  9. Click “Save”.
  10. No other settings had to be turned on/off for me to finally get this working, despite numerous other online guides suggesting otherwise.Firewall HomeSubnet

About JoeDania83

IT Administrator for a three campus non-profit.
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One Response to AT&T Uverse Internet with 5 Static IP and 3rd Party Router

  1. JD Smith says:

    Thank you so much! This saved me immense time setting up my static IP and passthrough with a Linksys E1200 AP. I used the DHCPS-fixed setting to map to the MAC address of my AP, and per your advice I didn’t restart the ATT router despite it asking me to do so to save changes. I am hopeful that after a power outage or reboot everything will keep working as is.

    A helpful tool to verify your IP range is:
    Just enter one of the IPs in your range and your subnet mask ( if you have 8 static IPs.)

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