Frequent loss of internet connection has me stumped ideas anyone???

Question

I have an almost new 24" Imac and I have been having connection issues recently with Comcast and I am going, no wait am insane. I had a Belkin router that was going flaky and got a new one but it was worse than the old one and after trying no router for a week and no lost connections I bought a Linksys and it was great for about 3 weeks and then suddenly loss of connection again. I used to have both a G4 QS733 and also an Intel Mini that had similar problems, the Mini was so bad in fact I ended up exchanging and selling the new on Ebay without even opening it up. I have replaced EVERYTHING in the past year startiing at the pole every cable and ethernet cable as well as the modem and the router (3x on that) and the computer has been changed out. I noticed when this happens my pc is still able to connect which makes it even worse because it all leads back to the apple being the problem. I noticed the problem returned a few days ago and I think it was right after a bunch of updates ( I currently am running 10.4.10) so maybe that is the problem??? Just seems weird to have a total of 8, yes 8 macs have the exact same problem but I have had about 40 different pc based laptops hooked to the same connection at various times and NONE had a problem. I get the feeling this is a simple incompatibilty issue between the Apple and the routers but I am out of ideas.
24" iMac 400 Pismo Panasonic Toughbook cf-28 for work   Mac OS X (10.4.9)  

Answer 1

Hi Tim Hartzell!
I may be off-base here, and my apologies if so, but I have a feeling you're having exactly the same connection issue with each of your Macs, not because they are not compatible, because they are in fact compatible, but due to misunderstanding how to perform one particular step of the initial setup of the Mac. This comment is not meant to slight you, as at one point I did EXACTLY the same thing and had the same results (I once used Comcast), and that's why I'm answering your question.
This isn't unusual if during setup of a Mac (the Welcome! procedure/program) you incorrectly identify and answer the question at the top of one particular page in the setup process:
"How Do You Connect to the Internet?"
Recall that one?
The question means how does your Mac connect - not how does your network connect. Therefore, if you are connected to Comcast via a cable modem, then have a router wired to it, and your Mac wired to the router with an ethernet cable, the answer should be:
"I connect to my local area network (LAN)."
You should NOT answer: "I use a cable modem to connect to the Internet."
If your ever change your Mac's connection back so that it is no longer connected to your network, but is instead connected directly to the cable modem, you'll find the same issue in reverse, and you'll have to reconfigure by answering with: "I use a cable modem to connect to the Internet."
The good news is that there's an easy fix, and you don't have to dig out the Install Discs and re-install your OS to fix your problem, nor do you reconfigure all your settings each time you change your connection method. Simply:
Open System Preferences, open the Network panel, click on the "Assist me..." button at the bottom of the panel, followed by clicking the blue "Assistant..." button in the drop-down box. [Do NOT click the "Diagnostics..." button.]
"Network Setup Assistant" will open while System Preferences will remain open behind it. On the "Introduction" pane, for convenience enter "ethernet to router" in the "Location Name:" box and click the "Continue" button. On the "How Do You Connect to the Internet?" pane, activate (by clicking) the radio button left of "I connect to my local area network (LAN)." and then click the "Continue" button.
Read and proceed. After configuration is completed you will see in bold at the top "Congratulations! You Are Connected." Click the "Done" button and Network Setup Assistant will close and quit. There should be a message box in front of System Preferences stating that "Your network settings have been changed by another application." That's as it should be, since you just used another app to make those changes, so click "OK" and close.
Finally, change the "Show:" selector to "Network Port Configurations" and select (highlight) the line "Built-in Ethernet" and simply use the mouse to drag the entire line to the top of the list. If you use wireless to connect to a printer, move "AirPort" into second position on the list, and follow by clicking the "Apply Now" button at bottom right.
The above will change none of the previous settings in other configurations that are maintained in the Network panel of System Preferences. The name of each of those different configurations is displayed in the "Location:" selector for you to choose how you wish to be connected. You should now see on that selector the name you earlier gave this new configuration - "ethernet to router"
While it may appear to be confusing, you'll notice that after you switch from one configuration name to another and have clicked the "Apply Now" button - the settings that you will see on each pane will be the ones that are appropriate for that configuration. That means that if you want to connect directly to your cable modem again, bypassing your router and your network, you'll need to change the "Location:" selector back from "ethernet to router" to whatever the current setting is called, followed by clicking the "Apply Now" button.
Once you have a working configuration, be careful not to edit any of its particular settings followed by clicking the "Apply Now" button, as that will alter the configuration so that it may no longer work.
Rather than haphazardly editing a working configuration, it's less confusing to simply initiate an entirely new configuration, as you've just done above. If that would then continue to work better for you, say for a month or so, then the prior configuration, and other old configurations, may no longer be necessary, and can be deleted from the "Location:" selector.