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You are here: MacNN Forums > Enthusiast Zone > Networking > A Strange Internet Connection Problem

A Strange Internet Connection Problem
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Senior User
Join Date: Dec 2002
Location: Canada.
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Jun 4, 2009, 08:34 PM

I have been helping someone with an intermittent internet connection.

- DHCP connection with automatic IP settings.
- Wired connection from LAN modem, no router.
- I have verified all settings are correct.
- Airport is turned off.
- She has a new modem from her ISP which is confirmed to be working fine.

What happens is the connection will work fine for a while, then she will get an error in Safari stating there is no internet connection. The modem is still online.

Now if she turns Airport on, then off, the wired connection is restored.

To me it sounds as if something in the system (.plist file?) is possibly corrupted. I am thinking maybe trashing the Network Preferences to see if it correct the issue, however I am not sure if this will actually work.

Can anyone provide some help?
..13" MacBook Pro | 2.53gHz | 4gb RAM | 320gb Seagate Momentus XT | OSX.6.6.. // iPhone 4 32gb
Cold Warrior
Join Date: Jan 2001
Location: Polwaristan
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Jun 4, 2009, 09:52 PM
First, create a new user account and see if that one has problems too. This will help you figure out whether it's just her account or system-wide.

Second, if it does affect the other account, then consider a potentially bad ethernet cable from modem to computer (I assume it's ethernet and that's the only one in the chain since you don't have a router). Switch out cables and see how it does.
Join Date: Oct 2001
Location: San Jose, CA
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Jun 4, 2009, 10:22 PM
I'd also watch the lights on the modem to make sure the Internet connection isn't going down. Is this DSL or cable? If it's DSL, I had an issue where AT&T was very happy to offer me an upgrade to 3 Mbps, which the web page said would work fine. So I upgraded. But I kept getting and losing the Internet connection constantly, which I figured out by watching the connection lights on the DSL modem. It turned out that I actually was too far from the CO and could not support the faster connection, even though sales and the web site said I could!

Watch the lights on the modem when the connection fails. The lights are there for a reason!

Celebrating 10 years and 4000 posts on MacNN!
drnkn_stylz  (op)
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Join Date: Dec 2002
Location: Canada.
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Jun 6, 2009, 05:52 PM
It is a cable modem. None of the light are flashing (supposed to have 4 solid green lights when there is a connection). When the connection drops, the modem has no change at all. ISP has confirmed that the modem has been online the whole time these issues started, and has no intermittence or signal problems.

My friend was using a router, but we bypassed it to make sure it is not an issue with that.

We will also switch the ethernet cable with the one from the router and test that as well.

I don't see this person very often so I will comment back if there are any other questions or if none of these suggestions work.
..13" MacBook Pro | 2.53gHz | 4gb RAM | 320gb Seagate Momentus XT | OSX.6.6.. // iPhone 4 32gb
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