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strange networking issue

Hi,

some server in my company network have been having problem lately with they network connection. The connection to the server will randomly disconnect and resume several minute later. If we ping from the servers to any other servers or pc the connection to the server will immediately back to normal.

we have try to change the network card and cable and also the switch from a nortel switch to 3com and them to cisco switch but the problem is still happening. this cannot be a OS problem becouse some of the server win2003 and other are running fedore core.

when we ping the affected servers from other server the first packet will have reply but then all other packet will have timeout and the there will only be reply when we again a few minute later.

what are the things that can cause this kind of connection problem?

Reply to
robertncl
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duplicate IP, or even more strange, duplicate MAC, or wrong teaming setup, can cuase the problems you experience. Check your routers ARP for changing MAC addresses of the servers IP. Also worms/virus, like sd-bot, can give the symptoms you describe.

HTH Martin

Reply to
Martin Bilgrav

Could be a duplex issue, a bad NIC in the server or a cabling problem. If using auto/auto both sides MUST be auto, or both sides must be set to a fixed speed/duplex. Also, I have seen issues where gig ports only work correctly using AUTO/AUTO. Since you have a Cisco switch, have you checked the port for errors? After verifying the duplex settings, my next step would be to swap the server nic and then replace the cable.

Scott

Reply to
thrill5

just found the error, it is becouse the configuration error on one of the cisco router that corrupt the ARP table of other servers by making the MAC address corresspoding to serveral server point to the router MAC.

thanks for all you guys suggestion.

Reply to
robertncl

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