Diagnose Comcast Problems

No Internet connection? Here's what to do. At the end of each step, do something on your computer to ascertain whether the Internet connection has returned. One easy way is to examine the OOMA modem: if you wait a minute or two only to see a red (instead of blue) flower pattern on it, likely the Internet is not back yet. As each step is eliminated as the problem, move the next.

You can review generally whether there are Comcast outages in your area at http://customer.comcast.com, but you must know how to sign into your account to go there.

  1. Bounce all devices on the concentrator tableau in the storage room:
    1. Press and hold the power button on the uninterruptible power supply (APC UPS) until when released, the light goes out demonstrating that it's powered down.
    2. Shut the power off to the power strip that's plugged directly into the same duplex outlet as the UPS.
    3. Restart both these devices in the same order: UPS, then power strip. It takes a few minutes for the power up to take effect.
  2. Comcast Modem
    Examine the Motorola Surfboard modem that connects Comcast's cable to the house router. The lights should all be on solid except for the Link light, which should be blinking indicating traffic with Comcast.
  3. House Router
    Examine the house router. As of 2011 this was a TRENDnet DSL/Cable Broadband Router, TW100-S4W1CA. Ensure power is reaching it as a result of step 0 above.
  4. House Router
    Use a browser from a computer connected via hard wire to the router. Go to You should see the TRENDnet Router splash page with a login dialog. This means the router is functioning correctly.
  5. House Router
    Log into the router using a User Name of admin and no password. You should see the set-up page.
    1. Click Advanced Setup.
    2. Click System in the navigation bar at the left.
    3. Click System Time underneath the System menu, note the Local Time, especially if it's bogus.
    4. Click Status underneath the System menu.
    5. Recode the WAN IP address; if, it means that Comcast DHCP isn't offering us an IP address. This is the smoking gun and means that Comcast will have to reset the modem from their end. (See next step.)
  6. Comcast Support
    Call Comcast support at 1 888 262-6300 and explain the problem. A machine will ask questions such as:
    1. What the problem is; say "Internet."
    2. Another questions about what the problem is; say "Internet" again.
    3. Decline any surveys they pre-offer.
    4. You may need to give the last four digits of the Social Security Number. These are xxxx.
    5. Wait for the service representative (human).
    6. They will ask for credentials such as telephone number, nnn nnn-nnnn, house address, xxxx xxxxx xxxxxx xxxxxx and the name on the account.
    7. At this point, they will likely visit the question of whether their modem is functioning correctly (see Comcast Modem above).

    Now you should reach a human being.

    1. If they say they can see their signal reaching the modem, then likely the solution is that they need to reset the modem.
    2. They will ask you to observe the reset during which you'll see most of the lights on the modem go out, then begin blinking on gradually until the modem has rebooted, the state described above.
    3. After the modem has rebooted, ensure the rest of the concentrator equipment is powered up and return to the hard-wired computer.
    4. Follow the instructions for the second House Router step above, but don't worry about System Time. Instead, go to Status and, if there isn't a real WAN IP address click on Renew. You may have to log in again to verify that the WAN IP address is renewed, something that looks sort of like nnn.nnn.nnn.nnn.
    5. You can dismiss the TRENDnet Router connection page adn you should be able to bring up a page on the Internet, do e-mail, etc. that only work when the Internet connection is healthy.

TRENDnet DSL/Cable Broadband Router

Besides what's described above, this router is used to wire up protocols via ports from the outside world in via the Advanced Setup -> NAT -> Virtual Server settings:

Server IP Mapping Ports Type Enabled (HTTP) 80 TCP x (SSL) 22 TCP x (HTTP) 8888 TCP x (SSL) 9922 TCP x (HTTPS) 443 TCP x