iMac won't stay connected to network (wireless or ethernet)

[am1971]

We've got two macs in the house both connected to a wireless network. Everything was working fine until last night.

Now one of the macs (iMac 17") will not stay connected. If I turn airport off then on it can access internet for about 30 seconds, then stops. I thought it might have been the wireless router but I tried another one I have in the house and the problem is the same.

I thought it might be a distance issue so I moved the iMac into the same room as the router and it's the same. I then connected the iMac directly to the router with an ethernet cable and the exact same problem occurs. I tried to make a new location in the Network prefs but that doesn't help either.

In the meantime the other mac and my iPhone can connect to the wireless network and have no connection issues at all.

And when the connection on the iMac is dropped I can access the router via my browser with no trouble at all.

At this point I haven't got a clue what to try next so any advice anyone could offer would be great.

 

[scotpole]

Is it plugged in?

Sorry for the sarcasm, but sometimes look for something simple.

First turn off your modem and your router for ten seconds. Sometimes what happens is your modem or your router get a surge and get scrambled up. By turning them on and off you may clear out any uncertain states that they have. I sometimes see this after a lightning storm.

Check your connections. An ethernet connection or modem wire could have come lose.

Go out to system preferences and see if it is giving you a green light on the airport under the network icon. Also check system prefs to see if somehow you have inadvertantely set the computer to sleep.

If you go the utility folder in applications, you will find an airport utility. If you open this it will allow you to configure your airport. If you are not using an airport, trying configuring your router with the software that came with it. Also check if the software has a diagnostic routine for the router. The router may be fried.

If you got the router with out instructions you might want to check out the manufacturers web site. They may provide you with a direct number that can be interfaced in a browser to communicate with the router. The number will be something like 192.00.00.00. You might me able to make changes manually to the router using your browser. You should probably enable DHCP. This allows computers to join the router and the router assigns a number based on availability. First come first served.

If you are having problems with a printer under DHCP, assign the printer a permanent address using the printer's control panel or the printer utility software that came with the printer. Such an address would be something like 10.0.1.19. Sometimes when you log onto a printer on a network you set up a printing address in your printing software and as long as your computer and printer stay on everything is fine. But when you restart or repower up the computer and the printer may be reassigned new addresses under DHCP. Your computer has the old address and the printer has moved to a new address. Your computer might not be able to find the printer. If you give the printer a permanent address your computer can always find it.