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
You can review generally whether there are Comcast outages in your area at
you must know how to sign into your account to go there.
- Bounce all devices on the concentrator tableau in the storage room:
- 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.
- Shut the power off to the power strip that's plugged directly into
the same duplex outlet as the UPS.
- Restart both these devices in the same order: UPS, then power strip.
It takes a few minutes for the power up to take effect.
- 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
- 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.
- House Router
Use a browser from a computer connected via hard wire to the router. Go
to http://192.168.0.1. You should see
the TRENDnet Router splash page with a login dialog. This means the
router is functioning correctly.
- House Router
Log into the router using a User Name of admin and no
password. You should see the set-up page.
- Click Advanced Setup.
- Click System in the navigation bar at the left.
- Click System Time underneath the System menu, note
the Local Time, especially if it's bogus.
- Click Status underneath the System menu.
- Recode the WAN IP address; if 0.0.0.0, 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.)
- Comcast Support
Call Comcast support at 1 888 262-6300 and explain the problem.
A machine will ask questions such as:
- What the problem is; say "Internet."
- Another questions about what the problem is; say "Internet" again.
- Decline any surveys they pre-offer.
- You may need to give the last four digits of the Social Security
Number. These are xxxx.
- Wait for the service representative (human).
- They will ask for credentials such as telephone number,
nnn nnn-nnnn, house address, xxxx xxxxx xxxxxx xxxxxx and the name
on the account.
- 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.
- If they say they can see their signal reaching the modem, then
likely the solution is that they need to reset the modem.
- 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.
- After the modem has rebooted, ensure the rest of the concentrator
equipment is powered up and return to the hard-wired computer.
- 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.
- 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
| 192.168.0.100 (HTTP) || 80 || TCP || x |
| 192.168.0.100 (SSL) || 22 || TCP || x |
| 192.168.0.102 (HTTP) || 8888 || TCP || x |
| 192.168.0.102 (SSL) || 9922 || TCP || x |
| 192.168.0.102 (HTTPS) || 443 || TCP || x |