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cisco switch voodo

Posted on 2013-11-15
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Last Modified: 2013-11-17
I had my layer 2 netgear switches replaced with layer 3 cisco managed switches and for the most part everything pings everything, except for one windows 7 workstation that can ping everything but nothing can ping it, see it, share with it...  when I had the dumb netgear layer 2 switches everything worked.  Anyone have a clue why a machine that worked before, when put into a cisco based managed switch network would all of a sudden loose the ability to be seen on the network, yet at the same time, it can see everything on the network?

Topology - 10/100/1000 L3 SW -> 10/100 L3 SW -> Cisco Router
Might be :
10/100/1000 L3 SW -> Cisco Router -> 10/100 L3 SW, I'd have to look, if it matters...

The 10/100 L3 SW and the Cisco Router have gig ports.  On the 10/100 there are 4 uplink ports.  On the Cisco Router, the ports are gig.  Plugging the workstation into either the gig uplink on the switch or the gig port on the router results in this behavior where the workstation sees the network ok, but nothing on the network can see it.

Thanks,
gsgi
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Question by:gsgi
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Expert Comment

by:justind39
ID: 39652821
Can you ping that computer from the switch?
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Author Comment

by:gsgi
ID: 39652824
nope.  not from the switch or the router, regardless of whether the workstation is plugged into the switch or the router.

it's voodo!

thanks!

gsgi
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justind39 earned 500 total points
ID: 39652832
Ok I assume that the ip address of the Win7 is on the same subnet as the others and that the firewall is off.  Do you have any Norton Security or anything similar?
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by:gsgi
ID: 39652839
Same network and subnet, yes.  No firewall software, norton or anything that I can think of but I will double check in the morning.  Even if that software exists, a change from a L2 switch to a L3 switch should not cut off communication to this workstation.  All we did tonight, was add a L3 switch to this network, the first one (leftmost) in the topology diagram I sent.  Oh, and we replaced a cisco router with a different cisco router.  But, this workstaion has been in the gig port of the L3 10/100 switch for three weeks.  So what could possibly cut off communication back to it???  The fact that it can ping, and receive the successful ping traffic back is interesting because other than that it seems like it is not on the network... weird!!!!!
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Expert Comment

by:Rich Rumble
ID: 39652840
Time to get wireshark installed on the win7 and see if traffic is getting to it, and if's responding. If traffic is coming in, but no machine response, then it's a firewall. You may also check your switch logs, there could be a connection issue/bad port/ severe packet loss et.c.. Also note that 3rd party AV often comes with it's own firewall, make sure you have all firewalls disabled for your testing.
-rich
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Expert Comment

by:Craig Beck
ID: 39653332
Can you post the config from the Cisco switch?  I'm guessing it's because the PC is connected to a trunk port which isn't configured (properly).
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Expert Comment

by:Rich Rumble
ID: 39653367
Redact/Remove any passwords/hashes or public IP's if you do post a config.
-rich
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Author Comment

by:gsgi
ID: 39654012
This turned out to be a firewall issue.  Even though this workstation was already in this switch and happy, and even though we didn't change the network subnet or ip addresses or anything else, windows 7 sees it as a new network.  I set it to "work" and it was OK, but upon rebooting it goes back to public.  I have no idea why.  Anyway I just totally disabled the firewall for both public and home/work in the windows 7 config area and it is ok now.

Thanks,
gsgi
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by:gsgi
ID: 39654015
Thanks!
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