Wired Networks Thread, Network failure in Technical; Everything gone smoothly for first two days back, then mid morning today network seems to go down. I was installing ...
5th September 2012, 09:24 PM #1
Everything gone smoothly for first two days back, then mid morning today network seems to go down. I was installing software on a laptop from the domain server software drive when I lost network connection, went to check the server, it was still up and I could log on, internet access still available but I couldn't ping the wsus server or access any of the computers on the network. The wsus server was still up but couldn't ping the domain server.
Suspecting a loopback I walked round school, couldn't see anything, no computers in school had access to either of the servers. Rebooting the servers didn't make any difference, so I went back round school turning off access points, laptops and computers (very unpopular at this point), then unplugged patch cables from the switches of the computers that weren't turned on yesterday (if that makes sense). At which point the two servers could ping each other.
I then turned everything back on indivdually and replaced each patch cable in the switches, all is now ok but I'm non the wiser why the whole network failed.
Any ideas what I should be looking for to check it doesn't happen again.
5th September 2012, 10:55 PM #2
Were any of the switches showing broadcast storms?
Do you have STP? and do you have BPDU guarding?
It's possible somone created a loop, filled the network with a broadcast storm and then removed the link.
Do your switches have history loggs?
5th September 2012, 11:12 PM #3
No sign of broadcast storms, they are bog standard unmanaged switches.
5th September 2012, 11:22 PM #4
Well next time it happens run round every switch and see if one is going balistic...
If that shows no obvious sign of issue then I would be disconnecting everything from the switch your servers connect to appar from the servers, if pings are not restored then you either have a faulty switch or a conflict.
6th September 2012, 12:21 AM #5
Thats basically what I did, only tbings running were the servers, at which point they could ping each other, then turned everything back on in small groups.
Originally Posted by twin--turbo
6th September 2012, 01:57 PM #6
Have you got Spanning-Tree turned on ? What switches have you got ?
6th September 2012, 03:18 PM #7
Originally Posted by chrbb
6th September 2012, 03:25 PM #8
Ohhh aye sorry - must of read that post too quick!
6th September 2012, 03:42 PM #9
If you can find a small budget to at least upgrade to a smart switch for the servers that will start to show some diagnostic benefit. Good second hand switches are on ebay all the time too , you can get a lot of specification for a little bit of money and if it saves half a days lost teaching then it is money well spent.
6th September 2012, 03:53 PM #10
Could be a switch on its way out, we had that on Tuesday. A fully populated 48 port switch decided to off itself in the morning, unfortunately every big high volume printer in the place was on it, eep, cue enraged people very nearly smearing their own blood on paper just so they could consume their daily dosage of tree.
You can sometimes bring back a crashing switch by yanking the power for 10 or so seconds then plugging it back in.
6th September 2012, 03:56 PM #11
As others have said, buy a few managed network switches, turn on STP option and you will never have loopback problems again
Otherwise, in this case again, start a ping -t to the server then go round and isolate each switch (or port). As soon as you find the broken one the ping should restart.
6th September 2012, 04:12 PM #12
Our first switch we had made by planet (going back probably 10 years), Randomly started locking up it's uplinks to our remote buildings..
And about 2 years ago we had an 18 Month old Cisco 3560-24POE kept randomly locking up, a fair amount of time was spent on that including an IOS update and eventualy managing to rais a TAC with cisco via the reseller and get it replaced. It's little known but cisco fixed configuration switches do come with a limited lifetime warranty.
6th September 2012, 04:22 PM #13
And no free firmware updates, getting Cisco is expensive, keeping it is even worse. Their gear is usually epic though.
Originally Posted by twin--turbo
19th September 2012, 05:15 AM #14
Incorrect. All Cisco Desktop Switching Business Unit switches (2K, 3K) come with IOS upgrades at no additional cost, for the lifetime of the product. This includes both fixed and stackable versions.
Originally Posted by SYNACK
Thanks to Destinova from:
SYNACK (19th September 2012)
19th September 2012, 07:28 AM #15
Well they have changed that then, where do you sign up for that and is it avalible outside the US?
Originally Posted by Destinova
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