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LAN won't connect to internet after power failure

But single computer will connect

         

akmac

6:29 pm on Jul 12, 2006 (gmt 0)

10+ Year Member



My LAN consists of 7 computers in an 8 port linksys router (wired) connected to the internet through a cable modem.

Some months ago after a power failure-our access to the internet from the network *ended. In the course of troubleshooting, I thought I had isolated the problem to the router. A single computer connected directly to the modem connected to the internet just fine-so it must be the router, right? So we bought a new one-same problem. Linksys tech support set us a new one-didn't help. They were boggled, I was boggled.

A friend mentioned that I should try replacing the modem-which didn't make sense to me-so I did it anyway. Bingo-problem solved. This led me to believe that the modem was the problem-something in the power failure or surge had damaged the modem in such a way that it no longer functioned connecting to our network-but worked fine connected directly to a single computer.

This opinion was reinforced when some months later, we had another power failure. Same problem. This time, I exchanged the router straight away-with the expected positive result. The problem was solved-it was the modem.

Until yesterday. Another power failure (small community in Alaska). So, I felt supremely confident that the problem could be fixed by replacing the modem-as it had two times past. But-this time the new modem doesn't fix the issue. And neither does the second modem I try. 15 power cycles of both modems and router later-I'm baffled. Anyone familiar? Help? Please?

akmac

7:40 pm on Jul 13, 2006 (gmt 0)

10+ Year Member



Oops-meant to say I exchanged the MODEM straight away-not the router. Exchanging the modem has fixed the problem-twice.

An interesting wrinkle-when I power cycle the router, the network will connect for about 10 seconds to the internet before it loses the connection. I've got a new router on order as well-just in case. grumble.....

mack

8:04 pm on Jul 13, 2006 (gmt 0)

WebmasterWorld Administrator 10+ Year Member Top Contributors Of The Month



Does the router run dhcp? Perhaps the IP addresses have been assigned wrongly. Where you using a static setting on your systems but still running dhcp.

I know this sounds like a crazy thing to do but, been there and bought the t-shirt.. took me a while to figure out.

Mack.

akmac

8:09 pm on Jul 13, 2006 (gmt 0)

10+ Year Member



I have one machine using a static ip (to interact with some web aps) the rest are assigned using dhcp.

jtara

4:05 am on Jul 14, 2006 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member



I have one machine using a static ip (to interact with some web aps) the rest are assigned using dhcp.

Although this is almost certainly not the cause of your problem, if you are using DHCP, then I'd recommend using DHCP on ALL machines.

You can use DHCP to assign a static address to any machines that need a static address. You will need to know the MAC address of the machine's interface. You can then set-up DHCP to always assign the same IP address to that MAC address.

By having all of your address configuration in one place, it eliminates a lot of potential for misconfiguration.

As to your problem - you should be able to diagnose the problem using ping and traceroute. Can you ping the router? The modem? The gateway address at your ISP?

kaled

1:15 pm on Jul 14, 2006 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member



Firewalls are the source of many mysterious network problems.

Kaled.

akmac

8:36 pm on Jul 14, 2006 (gmt 0)

10+ Year Member



Jtara-

What i've done is have the static ip -100, and the dynamically assigned ip #'s to begin +100. Linksys tech support said this should work fine-but I do think I'll use your method instead as it's a bit more elegant.

Yes, I can ping the router-the connection problem seems to be intermittent. My new router should arrive next week and I'll see if it fixes things.

All ideas welcome...

vite_rts

9:09 pm on Jul 14, 2006 (gmt 0)

10+ Year Member



inntermitted, or inconsistent problems are almost always hardware related,

setup issues are usually consistent, it either works or doesn't

I am guessing you don't use a UPS, well a power surge before or during your power failure would easily fry the delicate bits of your router, or modem

Strange tho, cos most routers are protected by their DC power pack, sounds mad, mmmm,

but if the power packs are no longer delivering the right power, then the router an modem would be os

Get youself a UPS

You might

aspdaddy

9:30 pm on Jul 14, 2006 (gmt 0)

WebmasterWorld Senior Member 10+ Year Member



I dont think the power failure would break the gear, but a surge defineetly could.

You can get a surge protector and a 500VA UPS for about $50. Thats plenty to protect a modem and router.

akmac

9:41 pm on Jul 14, 2006 (gmt 0)

10+ Year Member



Both are plugged into a UPS-which is plugged into a surge protector/power strip. Or should have been. I know that the computers are plugged into the UPS, and at the very least the modem and router are in a power strip with a surge protector.

Hardware failure. That should be a t-shirt.

vite_rts

10:02 pm on Jul 14, 2006 (gmt 0)

10+ Year Member



well , tis the router an modem we're on about, are you certain that they were protected from power surge, the way you describe it, you ain't sure.

a simple, fuse protected strip might not cut out before the power got thru to the power packs.

Anyways,

power cut

+

incessant replacing of routers an modem

= what

Afterall, if this only happens at power cuts, and the equipment is 100% protected from power surges, I am baffled
it would be interestin to hear the solution to this

akmac

6:06 pm on Jul 18, 2006 (gmt 0)

10+ Year Member



It was the router. I replaced it and the problem is solved. The modem and router power cords have been moved from the power surge strip to the UPS as the strip doesn't seem to protect. Thanks guys. Lesson learned:

PLUG ALL CRITICAL HARDWARE INTO UPS