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SAbboushiFlag for United States of America

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Intermittent internet connection

I have a client that has a W7 pro pc and a VOIP Handset plugged into an ethernet switch which is connected to an Access Point.

With regularity (every day or two), they say they are losing internet connection:
PC shows "Can't display page" when trying to browse internet
VOIP handset calls drop completely

The client has been restoring the connection by rebooting the PC once or twice, but that makes no sense to me as I cannot see how that would have any effect on restoring the VOIP handset connection

I'm going to visit the client ASAP and am looking for a laundry list of steps to take to diagnose and resolve the problem.

Thanks for any help--
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John
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plugged into an ethernet switch which is connected to an Access Point.

Is the access point Wireless and is Wireless intermittent or dropping out?
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John asks an excellent question about the Access Point.  How do the workstation and handset get access to the internet after the Access Point?  Is there a switch on it to which the router is connected or is the Access Point acting as the router (then it's not really just an Access Point), or is there something wireless going on here?

There are several things to look at here.  Unfortunately, most are only useful when the problem is occurring.

Are the workstation and the handset plugged into the switch separately?  If so then the problem is likely not in either of those two but in the switch or further downstream.

When the problem is occurring, can you ping the access point from the workstation?  Can you ping the router?  Can you ping the internet by number (such as 4.2.2.2)?  Can you ping the internet by name (such as google.com)?

When troubleshooting intermittent internet connectivity issues, I usually create a simple .CMD file to run ping commands to a number of locations, in order from the workstation to the internet (by number and then by name).  Then the client can run the file when there is a problem and identify where the break is.  You can even direct the output of the file to another file so you can inspect the results.
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ASKER

Thanks for the responses.

AP is wireless.

is Wireless intermittent or dropping out?
The AP is wireless, but no user devices are connecting wirelessly to the AP.

I believe the AP is also acting as a router which is wirelessly connecting to (I suspect) a router in a separate nearby office.

Are the workstation and the handset plugged into the switch separately?  If so then the problem is likely not in either of those two but in the switch or further downstream.
Yes, which is why I don't understand how rebooting the PC would resolve the outage for the handset.  Any thoughts on that?

When the problem is occurring, can you ping the access point from the workstation?  

To identify the ip of the AP, refer to the "Default Gateway" address of the PC's LAN adapter using  ipconfig?

What tools can I use to examine the connection of the AP to whatever it is wirelessly connected to (or whether that connection has dropped)?

When troubleshooting intermittent internet connectivity issues, I usually create a simple .CMD file to run ping commands to a number of locations, in order from the workstation to the internet (by number and then by name).  Then the client can run the file when there is a problem and identify where the break is.  You can even direct the output of the file to another file so you can inspect the results.
Sounds like a great diagnostic approach - thanks.

Similar to question above, how can I get the names/ip addresses of all the devices between the PC and the internet during a period when the connection is working?
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John
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I visited the site today:

I would see if everyone could stay off the switch - maybe disconnect it for 30 minutes. Hook up a known good computer to the Access point. Does it lose its connection
I plugged my laptop directly into the AP (it only has one port).  Worked fine.

Here's what I've found:

Access Point: Intellinet Wireless 300N Access Point - 1 port on back

Switch: Intellinet 5 port Gigabit Ethernet Switch

AP, PC and Handset are plugged into Switch

AP is connecting wirelessly to Linksys Wireless-N Home Router WRT120N
A 2nd handset is plugged into the WRT120N

The WRT120N is plugged into a Comcast Business Gateway: CISCO DPC3939B

Observation:
The client says that the 2nd (wired) handset works  when the 1st handset stops working.

If so, then I believe that suggests there is a problem with the switch, the AP, or the wireless component of the WRT120.  I'm waiting for client to confirm 2nd handset doesn't also go down before taking next steps.

When the problem occurs, I believe I can diagnose by:
1) pinging the AP
2) pinging the Linksys Router

However, how would I know if the switch is the problem?
 
Any thoughts appreciated.  And thanks for all the help.
You would know that the switch is the likely problem if a computer attached to it cannot ping the Access Point.  I'd test that when it is working properly to confirm the assumption that the Access Point replies to pings.

Is it impractical to run a wire in place of the wireless connection between the Access Point and the WRT120?  What about temporarily doing that?
I'd test that when it is working properly to confirm the assumption that the Access Point replies to pings.
Thanks - great point!

Is it impractical to run a wire in place of the wireless connection between the Access Point and the WRT120?  What about temporarily doing that?

Impractical.  

After diagnosing the problem, it makes sense to me to reconfigure the AP to connect with the Gateway and take the Linksys Router out of the equation.  On second thought:  configuring the AP to communicate with the Gateway looks like a good next step.  If there's still a problem after that, then I believe this narrows the problem to the switch or the AP.

Still don't know how to test if the switch is the problem though (other than process of elimination)?
If the AP can connect reliably with the Gateway that would be a better approach as it eliminates a device (the Linksys) along the way.

As far as testing the switch goes, if you can reliably ping the AP when you are having problems connecting to the main router than the switch is not the issue.
K thanks again
FYI - I replaced the switch/AP/router with an amped|wireless AC750 Range Extender TAP-EX2.

Still having problems.  See here if you want to weigh in!

Thanks--