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Wired Networks Thread, Sudden 'Unauthorised network' issues on Domain in Technical; Hi, For some weird reason about four of our Win7 64-bit PC's have started failing to be able to contact ...
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    marsdenprimary's Avatar
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    Exclamation Sudden 'Unauthorised network' issues on Domain

    Hi,

    For some weird reason about four of our Win7 64-bit PC's have started failing to be able to contact our DHCP server. Just getting 'Unauthorised network' in the connection settings and can't change it from 'Public'

    EDIT: IT NOW SAYS 'UNIDENTIFIED NETWORK' and the 'unauthorised' bit has gone... :-/

    It's very strange as they were fine before. They are connected to a switch in a cab on the top floor which is fibred to another cab on the lower floor. This then connects via CAT 5e to our main switch.

    Does anyone know what it could be? I have tried the following already:

    - Removing the ethernet adaptor and reinstalling
    - ipconfig /release and ip config /renew (when doing this it fails to renew, even though it gets an IP assigned on boot up)
    - Removing from domain but then failing to be able to rejoin

    Help appreciated as it's driving me nuts!
    Last edited by marsdenprimary; 15th April 2013 at 03:02 PM.

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    anything else on that switch? might be worth dragging a known working laptop there disable wifi and see what it gets

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    marsdenprimary's Avatar
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    Quote Originally Posted by sted View Post
    anything else on that switch? might be worth dragging a known working laptop there disable wifi and see what it gets
    Only other thing on there is a Unifi Wifi access point... I'll grab a laptop and give that a whirl and report back.

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    marsdenprimary's Avatar
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    Okay well it did it with a laptop too... so at least it rules out the machines. I think i'd have preferred it to be the machines to be honest...

    Any other ideas?
    Last edited by marsdenprimary; 15th April 2013 at 03:03 PM.

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    EvLPhenom's Avatar
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    We have had this happen before. It has been something spamming the network.

    We find that the quickest way to identify it is to plug in a laptop. Disable wifi then run ping from a command promt to a ip address (usually a server) with -t. It will then report back saying that it couldn't connect or something to that effect.

    Remove patch cables until you get a successful ping back from the machine. Then just find where the patch corresponds to in the building.

    We have had printers wifi aps and computers all cause this problem in the past.

    Hope this helps

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    3s-gtech's Avatar
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    Do you have rogue AP detection running elsewhere which has singled out this AP to attack it? Certain network infrastructure/APs enable this, by DDoS'ing the AP.

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    marsdenprimary's Avatar
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    Quote Originally Posted by 3s-gtech View Post
    Do you have rogue AP detection running elsewhere which has singled out this AP to attack it? Certain network infrastructure/APs enable this, by DDoS'ing the AP.
    Just had a check and we do...although this shouldn't really affect wired machines should it? Are you suggesting I unplug the AP?

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    3s-gtech's Avatar
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    Perhaps - try it and see! Not massively confident on that one, but just wondering if that switch is getting flooded with traffic due to the AP being attacked.

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    marsdenprimary's Avatar
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    Right then. The problem has gone... Turned out it was the fibre optic link between cabs!!! Turned off the converters, turned them back on again, problem solved. Flipping crazy problem thanks for your help peeps!!!

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    It's BACK but in a different form... :-( Seems now the connection on the machines is intermittent. I'm definitely suspicious about the fibre optic converter...any experience of this? Tips??

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    Any device can fail I guess, have you got another set of converters you can try? Have you had any building work done recently near the fibre run, maybe its been damaged.

  12. Thanks to Torrevez from:

    marsdenprimary (29th April 2013)

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    my money is on dodgy fibre or transcievers,

    swap what you can logically, its hard if you haven't got spares.

  14. Thanks to ConradJones from:

    marsdenprimary (29th April 2013)

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    Fibre converters are pants! Use proper fiber SX or LX modules.

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    marsdenprimary's Avatar
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    Quote Originally Posted by Torrevez View Post
    Any device can fail I guess, have you got another set of converters you can try? Have you had any building work done recently near the fibre run, maybe its been damaged.
    We have had work done but i don't think it has been near the fibre link

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    marsdenprimary's Avatar
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    Quote Originally Posted by ConradJones View Post
    my money is on dodgy fibre or transcievers,

    swap what you can logically, its hard if you haven't got spares.
    Yeah that's my first port of call i think- going to order a new tranciever and take it from there :/

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