Network disappeared! help!! 1

[flaimster]

I have an ethernet 10/100 network with a pdc and a bdc running NT 4. there are 3 hubs and a switch. The problem is that suddenly today there seems to be no network. On the hubs and switch all the lights are green and the link lights on the back of the servers are green. Everything looks ok. I pinged and get the message "request timed out". pinged loopback address from the pdc and that worked. I am stumped. There is also a router/gateway and that cannot be pinged either. Any thoughts?

 

[jimbopalmer]

if the IP addresses work but not the names, it is the DNS resolution. I tried to remain child-like, all I acheived was childish.

 

[ChrisAC]

I don't think that it's DNS resolution if he can only ping the loopback address and nothing else!!

I presume that you've tried pinging other IP's on the network from various locations?

Does this affect just the PDC or can't you ping network addresses from any of the PC's or servers?

Chris.
************************
Chris Andrew, CCNA
chrisac@gmx.co.uk
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[GiaBetiu]

There can be many answers.
If it is not a DNS problem,... then
I can just give you few hints.
You said that was happend suddenly! => it was an event that trigered this. Was it a software changed? Are the switch/hub manageable? Was it a power surge failure?
I don't know how is your network configuration, but I supost that you have in the top of the tree the switch, and from there, going down, hubs.
If was a power surge failure, and your switch is down, the hubs are isolated.
Check the communication first between stations that use the same hub, then check between two stations that involve the switch in their communication.
Success! Gia Betiu
m.betiu@chello.nl
Computer Eng. CNE 4, CNE 5

 

[flaimster]

It doesn't seem to be a DNS problem. No computer can ping successfully and the Hubs and switch are not manageable. I have checked the connections between the hubs and the switch and everything is green...It all seemed to start when the router/frame relay/gateway (whatever) went down. That has happened before but usually the only consequence is that internet access is down for awhile. it is usually a Verizon problem.

Thanks for posting back so quickly. I love this site.

 

[Guest_imported]

Might be a silly question, but did you try rebooting PC's and/or hubs/switches?

Also what are you using to connect your network to the Frame Relay connection? Is it a router? If it is a router can you access the configs? Also check your ARP table and see if other PC's show up in the ARP table. Check this after a reboot to make sure that ARP entries aren't left over from when the network was routing properly.

 

[Tbarney]

I agree with GiaBetiu,
Boot the switch. Then the hubs. See if any segments come alive. I don't care if you have green link lights, I have seen a bad hub and/or network card take down a lan and a gateway router with all the lights looking fine.

You must be having one of those days...

 

[salserocito]

Start with one piece of infrastructure, either a hub or a switch. Plug 1 workstation and your servers into it. See if you are getting communication. Innot, try another one. If so, add a few more workstations and test. If your testing is successful, connect another piece of instructure and attach ONE workstation to it and test.

Good Luck.

 

[flaimster]

Thanks to everyone who responded! The culprit was the switch. Even though the lights were all green, the switch was blown. I replaced it and everything is working fine. You guys(and gals) are the best!
carla