
TROUBLESHOOTING the
Cisco 675 Router
This document will attempt
the fun task of helping you troubleshoot the Cisco 675. We will cover
the router in detail, and cover a bit of networking theory, cover all
possible causes of service interruption (all possible causes that I
can think of anyway) and in general try to go from A to Z here.
The
Easiest way to troubleshoot the Cisco 675 is to pay attention
to the lights on the front of the router. They are more than just
hypnotizingly pretty, they are extremely useful "At-A-Glance"
troubleshooting tools. Here is a diagram of all the Lights on
the Cisco. The Act Lights are yellow, the Link lights and Power
light are green, the alarm light is red. "Act" is short
for Activity, and indicate traffic flowing on the WAN (external
connection) or the LAN (internal traffic). "Link" means
that a connection has been established. At the bottom of this
document is a sample of the router's default configuration for
troubleshooting.

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This
is very close to what the Router looks like in normal operation.
The Power light is steadily green, The Lan Link light is steadily
green, and the Wan Link light is steadily green. Both the
Wan and Lan Act lights blink Intermittently. When a big download
happens, the Wan Act will go steady for the duration of the
download, and the Lan Act will blink faster. |
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If the
routers wan link light is blinking away at you prettily,
OR if the WAN link light isn't on at all, then there's something
wrong. Since this is on the WAN side, we need to check a
few things:
-
First, Check the configuration, make sure everything's
good there. Even if this has just started happening and
the router's been connecting without a problem, check
the configuration, as the router will on the rare occasion
corrupt it's config. If it's the latter case, chances
are pretty good you wont see the misconfiguration, Do
an nvram erase, and start over.
- Next,
make sure the lines are physically connected correctly.
(Lavender cable connected to the "Wall" jack
on the router and to the wall.
- Make
sure that there are no filters between the router and
the wall jack. Be careful when checking for filters, remember
that there is not only the "inline" type of
filter, which is obvious, but also make sure that the
in-wall-jack filter was not installed. The in-wall-jack
filter is like an old-fashioned wall plate, that phones
would hang on when wall mounted.
- If
the line is routed through a surge supressor, that could
be introducing noise into the line, try taking it off
the surge supressor.
- If
all this is good, it's time to call Qwest as it's likely
an issue with the line itself
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Does
everything look Normal, but your not getting throughput?
This is likely either windows being flakey, or a network
configuration issue.
- When
in doubt, reboot. Reboot the computer, and the Router.
How does one reboot the router you ask? Well, you can
either issue a reboot command through hyperterminal, or
go through the highly involved and technical process of
pulling the power cable out of the back of the router,
and plugging it back in.
- Make
sure that TCP/IP is configured correctly. It's the same
as a standard DUN connection, except you manipulate the
TCP/IP that's related to the Ethernet card instead of
the dialup adapter. You also need to plug in the gateway
of 10.0.0.1. Then you should be okay.
- Of
course make sure Client for MS Networks is installed and
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