HELP! iMac won't let me renew DCHP setting!

Okay so maybe you know of me from this thread

http://www.mac-forums.com/forums/os-x-operating-system/227360-need-some-assistance-5.html

....basically about two weeks ago now I had had little to no trouble using Comcast. The house is three floors. The modem from Comcast and the router from Belkin are on the second floor. The iMac is downstairs, if you went diagonal it would be about 10-20 feet.

So anyway this was not an issue of signal quality, it was an issue of the signal being read. Suddenly on a sporadic basis I had no Internet for webpages. Safari, Internet Explorer, FireFox -- kaput. They would just keep trying to load and load and load and nothing. This was not an issue of telling me 'Your computer is not connected to the Internet'; this was an issue of not being able to load a **** webpage.

Three days ago my iPhone decided to experience the same problem. Now it will update my Yahoo email inbox but I can't load webpages.

What was weird was I could use Terminal program on my iMac to connect to the Internet just fine so if I wanted to play text based hack and slash Dungeons and Dragons based games for eight hours that was fine. Just not my cup of tea; I'd rather browse the web!

So tonight I was downstairs playing with my settings. Yea I know bad move. Basically, now when I go to my TCP/IP settings, I get by default the option to Renew DCHP with manual address



When I switch to Renew DCHP lease and try to click it



It keeps switching me back to the manual address!




I promise from now on when this g.d. iMac has its "disappearing webpage connection" issue (and I'm sure it will, given that it's been at it for two weeks now) that next time I am just walking away and going outside or whatever. But for now I just need to get it back to picking up all three connections including the router. If I set the manually would that work? Think I tried that and it wouldn't take to the IP.

This is on TOP of this issue that it's had for two weeks. IT'S MADDENING. Sporadic Internet; I feel like I could quite literally bet on the odds of being able to get on the Internet through the webpages. That's IF I can get back on; I'm upstairs directly onto the modem and Ethernet as I type this. I may not even get to see responses until Monday at this rate.

Help please. This is just....insane. *sigh*

I hate to say this in here but this incident and these incidents have now officially marked me as a PC person. I only use this Mac because my father died in 2009 and willed it to me, and it has some of the same programs I currently require for college schoolwork.

I just saw an article in the latest Macworld magazine with someone having a similar problem. Their suggestion was to reset the cable modem, since sometimes they get weird about handing out addresses via DHCP. Most modems will reset if you leave them powered off for a couple minutes (yes, really a couple minutes). Others have a little battery in them and you have to use a paper clip and push a little reset button through a tiny hole, usually labelled "Reset". How long you have to hold it isn't clear, but often it takes about 3-5 seconds.

I don't know if this is what you're seeing, but since it seems to be affecting multiple devices it sounds lore likely to be a router or modem issue rather than the individual devices.

HTH - Good luck!

I might suggest a simpler solution - plug the Mac into the modem directly and get it to settle down. I also would stop trying to "make" the computer perform a la PC and let the Mac OS take control as it will continue to try and sort out the issue on it's own. Set it on Automatic and let the OS do it's job.

One thing I have noticed when fooling with DNS, network and router issues, sometimes setting the machine to a neutral state, save or OK out of the window and then restart the machine will help to clear things. Your router is set to DHCP so let the router do the IP work and let the Mac figure out the rest.

Also please mention what OS your are working with as these setting change by version, plus tell us the machine type. Last make sure your "preferred" method of connecting to the router is listed first as this will be the default. I am on 10.6.6, using 2 internal routers and hard wired.