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Computers can't ping eachother

Posted on 2010-09-20
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Last Modified: 2012-05-10
I have a very strange problem.
Computers can't ping each other on the same network.

In the labs at the College we use LanSchool and the teacher was unable to check students computers. When I check I did a simple ping from the teacher computer to a student computer and was unable to ping it.

I tested several other computers on the same lab and no computer can ping the other.

They are all using DHCP and connected to an AP (Cisco Aironet 1250). They all use a wireless card.

I check the firewall setting on our server and ICMP is allowing ech request and nothing is blocking that so I really don't understand what should be the next step to check what is going on.

I even tried Wireshark and I can't seem to ping to any other external IP exept the servers.

Internet connection is working ok tough.

Any ideas?
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Question by:SamKira
6 Comments
 
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by:teksamurai
ID: 33719730
Check if you have the Windows Firewall turned on for each of the PCs. They are on by default.

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by:1oo4
ID: 33719733
Try pinging both from the router. Could be a locally installed firewall.
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by:Qlemo
ID: 33720672
Definitely a local firewall on each PC. The servers are not involved in a ICMP between PCs. Remember, Windows Firewall default settings are to block all incoming connections, and allow all outbound traffic.
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by:pergr
ID: 33723539
It is possible that the Cisco Aironet 1250 is set to not allow traffic between wireless clients.
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by:SamKira
ID: 33724339
First reaction was to disable firewall on local machines. Microsoft firewall is off and there is no other firewall installed.

It is possible that the Cisco Aironet 1250 is set to not allow traffic between wireless clients.?
I don't think so, if it is would have to be the default since I've restarted the AP several times.
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teksamurai earned 500 total points
ID: 33734269
Your server or router may have a configuration to segment each PC as a separate user. This would typically be put in to keep one student from accessing another student's PC in the lab.

Check the IP, subnet mask, and gateway on at least 2 computers. The subnet mask should include all PC's in the lab.

You may also want to check with your sys admin. There maybe a third party package that is keeping them from communicating with each other. Some of these will hide their agent's installation to prevent student uninstall.
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