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Ping sometimes working and sometimes time out?

I am having a strange issue here. All stations and one server (all windows) connected to a switch in a network, same subnet. If i ping from server to any workstations or reverse, ping sometimes time out. I also tried to ping the router which connected to the switch from any stations, it also have the same issue.

I replaced the switch and routers - brand new, still having same issue. I even replaced network cable. What is wrong?
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Rob HutchinsonTech Lead, Desktop Support

Commented:
Maybe the autonegotiation is not autonegotiating...check to make sure, as a test, that you have the network card speed set to a manual speed, i.e. 100 Full/100Half, etc., for one of the servers and match the speed on one of the workstations to see if the ping problem stops.
Top Expert 2010

Commented:
>Ping sometimes working and sometimes time out?

This can be many things; you could be a victim of an attack or virus outbreak (Internally/Externally), could be related to network saturation on one or more links. You could have a malfunctioning NIC on a workstation or server that is causing an intermittent issue on the network. Too many users connecting to the server and causing congestion, etc

How often is this happening?
When did it start (Did you add something new to the network around the same time, maybe a new application, workstation, or server)?
Do you have a network diagram of the environment?

Billy

Author

Commented:
I tried to scale down the troubleshooting. so, I only had the brand new switch and 1 server and 1 workstation. So it's pretty easy here. Modem - router - switch - 3 pcs here. and they are having the issue as I mentioned above. I forgot to mention they got hit by lightening, so suddenly many devices are defective, modem, switches and router. But i have replaced them already. So I am wondering if the nic are bad as well?? all I have to replace whole pc?
Top Expert 2010
Commented:
>I forgot to mention they got hit by lightening
That is a big missing variable; what you can do is load up wireshark and run some packet captures to see if you see any odd traffic, with luck, there could be a bad NIC sending bad data (I have seen this happen). Otherwise, if you have two extra NICs lying around you could just replace those NICs in two workstations that have issues pinging each other and ping between those hosts to see if that resolves the issue. You can also pull the cables from two known hosts that are having issues pinging each other and install a cross-over cable and ping between the two , if that resolves the issue, then it could be related to other issues. If you can monitor the switch with a SNMP monitoring tool, that will give you an idea of the traffic utilization on the network.

Billy

Author

Commented:
and one thing I don't understand is that the router is brand new, why I got time out when i ping it from pcs? if the nic on the pc defective, even the router is good, i still get time out?

Author

Commented:
Thanx rfc1180. i think you missed  my question above.
Top Expert 2010

Commented:
>if the nic on the pc defective, even the router is good, i still get time out?
Not sure, maybe replacing the NIC; you are stating the the NIC on the PC is still defective, yet, you can the router and you still get timeouts.

Billy