# So today our office network connections just vanished..first internet, then all local



## Black Panther (Jan 20, 2011)

We have 3 networked pc's:

My personal work pc, let's call it pc A (Win 7 x86) which is the 'server' containing the software for running our company is wired to an external modem and to a router/switch. From the router/switch there's a wired connection to Pc B (Win 7 x86), and another wired connection to Pc C (XP x86) which is attached to the printer.

Till 11:00AM everything was fine. Suddenly there was no internet connection on all 3 pc's. But the local network was still functioning fine, pc's B and C could access the software in pc A and all 3 computers could access the printer. So I didn't bother much until my dad needed internet to check work correspondence. 

So we rebooted all 3 pc's.

After doing so, pc C became invisible, obviously together with its printer... We couldn't access it to print, and it couldn't access the company software on pc A.

I tried a system restore on pc C but kept getting the message that it was unsuccessful, no matter which dates I tried.

So we rebooted everything again - and went from bad to worse because now even pc B got thrown out of the network.

I checked the network settings on pc A. Something was surely wrong - the network was called "Unidentified Network" whereas before I'm sure it was called "Work....something" or "Home...something" 

I tried a system restore on pc A, only to get the same message that the system restore was unsuccessful no matter which dates I tried 

I can temporarily get stuff running for tomorrow's work (I'll unplug the printer from pc C and plug it into pc A and we'll use only one computer instead of 3...) but it's an inconvenient short term solution 

*
What could have caused this i.e. first the external internet connection got lost and then all local connections got lost as well?

Networking is a very cloudy area for me (I'm a n00b).. where do you suggest I start working to fix this?*


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## digibucc (Jan 20, 2011)

well if local is down your local router is down.

roadrunner, etc when connecting but not reaching their external gateway will say local only - 
but you are talking about an actual local network with file sharing, so that means your 
personal router. 

if you ONLY have an ISP modem, but with multiple ports - then that's it, otherwise it's your wifi/eth router.
it sounds like the router itself has died/bricked. it's possible it could be fixed but with a complete failure like
you are having, chances are it is only downhill from here.  

open command prompt, run ipconfig and come back with the ip address and gateway it gives you. 
a bricked router will often return a non-standard address, ie not an ISP or local address.



W1zzard said:


> are you using dhcp?



yeah i guess i shouldn't have just assumed that


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## W1zzard (Jan 20, 2011)

are you using dhcp?


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## Easy Rhino (Jan 20, 2011)

system restore wont do anything for you. this is a router issue. first thing you should do is reboot your modem and switch and router or whatever you use.


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## Black Panther (Jan 20, 2011)

W1zzard said:


> are you using dhcp?



I'm not sure but I don't think so.
When we bought the new company software the price included all installation and networking, so I didn't do anything myself (and have no idea what other people did since they installed everything during my 2008 xmas hols)



Easy Rhino said:


> system restore wont do anything for you. this is a router issue. first thing you should do is reboot your modem and switch and router or whatever you use.



I tried system restore just in case some Windows update caused conflict, especially considering the printer pc C runs on XP and the other two on Win 7. I did reboot both modem and router. However I didn't _reset_ the router.


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## Magikherbs (Jan 20, 2011)

I think its bad drivers. This used to happen to me, with some regularity, and I'm not on a network lol. That is untill Realtek released the drivers I'm currently using. 
Reinstalling the adapters and a modem/router reset should work.


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## brandonwh64 (Jan 20, 2011)

DO you have a diagram of your networks topology?


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## Easy Rhino (Jan 20, 2011)

seems to me that you need to invest in a small business server so you wont run into this kind of a problem. instead of just troubleshooting 1 machine you now have to troubleshoot 3. also, get a network printer!


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## W1zzard (Jan 20, 2011)

are your machines set to automatically get ip ? then dhcp = on
dhcp server = dead = machines lose their ip adresses = can't be reached anymore
since dhcp leases have timeouts, machines disappear at random points in time when their leases expire


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## digibucc (Jan 20, 2011)

Black Panther said:


> I'm not sure but I don't think so.
> When we bought the new company software the price included all installation and networking, so I didn't do anything myself (and have no idea what other people did since they installed everything during my 2008 xmas hols)
> 
> 
> ...



if it was an ISP installation, all the more likely you are using dhcp.


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## Black Panther (Jan 20, 2011)

Magikherbs said:


> I think its bad drivers. This used to happen to me, with some regularity, and I'm not on a network lol. That is untill Realtek released the drivers I'm currently using.
> Reinstalling the adapters and a modem/router reset should work.



I don't think something which worked fine since Jan 2009 could suddenly fail due to bad drivers.... 



brandonwh64 said:


> DO you have a diagram of your networks topology?



Here goes...








W1zzard said:


> are your machines set to automatically get ip ? then dhcp = on
> dhcp server = dead = machines lose their ip adresses = can't be reached anymore
> since dhcp leases have timeouts, machines disappear at random points in time when their leases expire



Thanks, I'll check that out first thing next morning.
(I certainly don't remember signing anything with expiring leases when we did all of this)


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## brandonwh64 (Jan 20, 2011)

So im assuming PC is outside of your network since its hooked to the modem directly?


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## Black Panther (Jan 20, 2011)

brandonwh64 said:


> So im assuming PC is outside of your network since its hooked to the modem directly?



Which PC are you referring to?

Everything is hard-wired. There are no wireless connections.

Both modem and router are wired to pc A.

Then through the switches of the router pc A is wired-connected to pc B and also wired-connected to pc C which in turn is wired to a printer.


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## brandonwh64 (Jan 20, 2011)

This is how it would be typically


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## Black Panther (Jan 20, 2011)

brandonwh64 said:


> This is how it would be typically
> 
> http://img.techpowerup.org/110120/topology.gif



There's a high chance you're correct there - I'm not at work right now so I can't check the wiring (and even had I been there I'd have no internet to communicate )

I never really tested there whether an internet connection functioned without powering Pc A at all but only the modem and router....

As I said I'm totally ignorant on networking.
I work with wireless connections at home, where I have 3 pc's too. And well if I power up modem and router (which are wired to my main pc) the other 2 pc's get a connection even if my pc is powered off (obviously). But I never tried running a program off the main pc at home through my laptop or my daughter's pc, so I can't compare like with like there.


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## travva (Jan 20, 2011)

i think brandon is on the right track. if you've got stuff set to rely on pc A being functional and something goes south with it, your network goes down. i'd suggest setting it up like he said and see what happens.


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## Black Panther (Jan 21, 2011)

This is weird. This morning everything functioned fine as if nothing had happened.

It's not like the system needed a shut-down, we shut down the system some 3 times yesterday.


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## W1zzard (Jan 21, 2011)

have you found out if you are using dhcp?


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## brandonwh64 (Jan 21, 2011)

What i would do if i was your network guys is what i posted earlier yesterday and have the router use mac address filtering with a small IP pool for visitors and then set all your firewall exclusions in the router. Another option is if you have a large office with PCs and VOIP phones, i would setup the router as mention and then after it i would add a 24/48 port cisco switch with PoE for your entire office


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## Black Panther (Jan 21, 2011)

The culprit is either the modem or the router.

It happened again, and I switched both of them off and on again, and both internet and network got restored.

Next time it happens I'll switch only the modem off and on (I suspect it's the modem because the router is less than 2 years old whereas the modem is ~ 15 years old! )


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## Mussels (Jan 21, 2011)

Black Panther said:


> The culprit is either the modem or the router.
> 
> It happened again, and I switched both of them off and on again, and both internet and network got restored.
> 
> Next time it happens I'll switch only the modem off and on (I suspect it's the modem because the router is less than 2 years old whereas the modem is ~ 15 years old! )



i was gunna say, your first post made it very clear that the DHCP server was inaccessible to the end systems, so something in that link (router/switch) was the problem.


my guess is router, if the modem went the router should still have all LAN traffic working (so no invisible printer/PC)


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## MilkyWay (Jan 21, 2011)

Rather than let the router assign ip addresses the network company should have set up addresses for each pc.

You can do that in the routers settings usually accessible via an internet browser an ip addresses to log into it, then set each pc to its new ip via the network properties (control panel) in windows. I don't know the technical terms but that's how i did my home network. This is also to do with DHCP, which usually randomly assigns ip addresses. I think what i done on my home network was reserve ip addresses for the different clients.

Definitely a DHCP issue.

EDIT: Yeah what Mussles said, the LAN should still work if the modem wasn't working correctly because all the modem does is connect to the internet.


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## digibucc (Jan 21, 2011)

it's rarely a dhcp issue specifically, and more often and more likely an issue with the 
router not working properly, and not assigning the dhcp addresses properly.  that's 
why i asked in the very beginning, what ip address it gives when ipconfig is run.

there are situations where assigned ips make sense, and situations where dhcp makes
 sense.  this is one where although assigned would have worked fine, there is no reason 
to say dhcp was the WRONG choice.  at this point, i consider it more likely that it is the hardware
of the router, and not a configuration issue. therefore static or dhcp it would have failed.

am i hard to understand or something?  we are no further than my assessment in the first post.


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## Black Panther (Jan 21, 2011)

digibucc said:


> that's
> why i asked in the very beginning, what ip address it gives when ipconfig is run.




Oops forgot about that:






___________________________________


And to answer W1zzard, yes dhcp is on:


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## digibucc (Jan 21, 2011)

Black Panther said:


> Oops forgot about that:



no problem, but now that you have it working it won't show what i was looking for.

all i was checking was if it returned a non-standard address, as in: instead of your 
192 there, it starts with 69 and then has some 254s in it.  when that happens it means 
dhcp is not working properly and you are being assigned a bogus address.

we already know that's the most likely option, so you can try ipconfig next time it 
goes down, but it's not necessary.

the fact that local went down too says it is your local router.  if it had just been internet, it 
would have been your cable modem (most likely).

you can try assigning ips statically , as in how wiz showed it - but the truth is
if dhcp isn't working properly, the router isn't working properly. if it's for work
my opinion is you'd be better off spending the cash on a new router, rather
than fight this one until it totally dies,

that's just me though. i do tinker, and do plenty of repair - but imo this is one thing that
is not worth trying to fix, when a replacement is so available and cheap. 
(compared to lost productivity and downtime)


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## Black Panther (Jan 21, 2011)

And here's a network map:

(The network is working fine right now, I guess the WS-COMMON isn't showing on the map because it's the only pc running XP whereas the other two run Win 7?)


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## digibucc (Jan 21, 2011)

yeah that makes more sense, and is a normal setup.


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## Swamp Monster (Jan 21, 2011)

Black Panther said:


> What could have caused this i.e. first the external internet connection got lost and then all local connections got lost as well?



Chinese are attacking! Sorry, could not resist


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