Internet Connection up and down in LAN

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ZetaKappa

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Sep 26, 2013
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Got a Lan with 30 clients, made some works on cables taking them to gb. Everything works fine. Everything is on a static Ip, no DHCP. Some Clients can't connect to the internet, but can connect to network drive. Others can connect to internet but dropping connection in ten minutes.

Any help? If You'd like other infos please ask me.

Thanks in advance
 
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Solandri

Solandri

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Jan 4, 2012
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Are you saying you made your own cables?

The most common mistake when making your cables is that the order of the wires goes 12365478, not 12345678
http://www.practicallynetworked.com/img/568b.jpg

If you make your cables 12345678, two of the signal pairs don't travel on twisted pairs, making them vulnerable to RF noise. This causes symptoms like being unable to connect, or connections randomly dropping, or working with one computer but not another (one ethernet card can have more signal strength than the other).

The green and blue pairs are ordered inside and outside to maintain compatibility with phone cables (RJ-11, 4 wires). The main phone line is the middle two wires, the second phone line the outer two. By maintaining this ordering for the two middle pairs on ethernet, you can plug a regular phone line into ethernet jacks and it'll work for phone signals.
 
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Z

ZetaKappa

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Sep 26, 2013
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10,510
Why i can share network drives and some connection, printers....Everything seems working fine except internet connection?
I've checked the cables on the patch and they seems to be ok in order 12365478

Cable from wall to patch panel - patch cord - switch
 
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Solandri

Solandri

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Jan 4, 2012
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If your hardware is fine, the next likely culprit I can think of for your symptoms is that DNS is not properly being propagated to the network.

Get on one of the computers which can see a network drive but not the internet. Open a command prompt (start -> run -> type cmd). Type ping 8.8.8.8.

If you get a response, your internet is working fine, you just have a DNS problem.
 
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Solandri

Solandri

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Jan 4, 2012
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Could be a problem with the cables in the walls then. Looking at your pic, it looks like you have a lot of problems. It should be OK on all four pairs for a good connection, with all lengths for a port being the same and under 100 (if they're in meters).

As for why the problems cropped up now, 100bT only uses the two middle pairs. Gigabit uses all four pairs. The Abnormal pairs might have worked with the greater tolerances of 100bT, but are not working with Gigabit. Port 28 is the only one with a short or Open (unconnected) wire in the middle two pairs, so it's the only one guaranteed to have had problems with 100bT. You may want to try forcing the ethernet card on one of the problem computers into 100bT mode and see if the problem goes away.

Do you have a ethernet cable tester? Might be worth getting one if you don't. Plug it into the ethernet ports in the walls to see if those are wired correctly. If they're miswired, it's relatively easy to fix (unless a wire is physically broken). You just have to take out the RJ-45 keystone from the wall socket and rewire it.
 
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