Instable network

Posted on 2001-09-17
Last Modified: 2008-03-06

I recently installed 10/100 cards in my network (WINNT4 peer to peer workstations) and a Switch (100MB). The network I have is based on TCP/IP for there is also an ADSL gate to the Internet.
All computers have TCP/IP and specific IP (local 192.168.1.x) addresses.

The thing is that the network sometimes starts good, but in an hour or so one or more workstations don't have access to the network anymore. I can't find the reason for it. Cabling etc. seems tobe ok (could it be tested....). switch and cards are new.

kind regards

Question by:orenda
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LVL 17

Expert Comment

ID: 6488119
Can you be more specific? How many workstations? What make and model of network cards and switch? Does one machine go down or all? Trying pinging one machine to another and so on until you see if it is one machine acting up. Use the command ping "ip address" to work thru this.

Author Comment

ID: 6488248
Yes I can!

There is for example 4 workstations, all cards are realtek 8139 10/100 chipped cards. The switch is 8 ports edimax. most of the time when one goes down (only LAN en net-access go down) others will follow. So at elast 2 go down at that moment. Sometimes I have access through the "network-connection" in the "this computer"-screen but not in the network-browser. [[I use "" because I have a dutch NT4 and do not know the english equivalent]].
So sometimes I have also Ping-access (but not all the time). I am thinking that it could have to do with the half/ full duplex and 10/100 autosensing disfunctioning. So maybe I put just 100 and full/ half (which one is fastest?) in.

Any more questions? Glad you already looked into it....

LVL 17

Expert Comment

ID: 6488268
100 full duplex is fastest. I would start setting it manually if you believe this is the case, on each network card to see if this fixes it. Normally if all machines go down, I would have to say it is the hub. Is there any way that you can get another hub to try with your setup?
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Expert Comment

ID: 6488301
Hi orenda,
This is just a long shot, and may not be the case at all if you are statically assigning your IP addresses. If you are by chance using DHCP, and the lease period is somehow set too short, perhaps this could be the problem.  Worker

Author Comment

ID: 6489754

Well the thing is that never the network of all machines goes down, and not even specific machines go down. I setup all machines with Full 100 this morning and everything seems to be ok (4 now). Another thing I am just wondering about is still the quality of the network-cabling. It is all Cat5 cabling, so supposedly good. On the other hand maybe connections can be bad or something? Is there any way to test it (software or something?)?

Thanks, well the thing is I have fized (LAN) adresses on the workstations (192.168.1.x, Subnet-mask). So nothing can be wrong there I think!

I keep you updated on teh Full 100 workings...... If it works through today and tomorrow I will accept this as solved....

Kind regards,

LVL 17

Accepted Solution

mikecr earned 100 total points
ID: 6490093
If it is working then then cards could not automatically negotiate their connection with the switch. Once you set it manually, they're probably going to be happy campers. To be able to test a cable properly you'll need something like a fluke or toner to test them. I don't think it's the cable at this point because if you were having problems with all the machines I could not anticipate cables being bad on all of them. Let me know how you make out.

Author Comment

ID: 6491557
well... by he end of the day I lost again several machines......
I was thinking that probably the setting of autodisconnect in the registry to a certain value that is large enough could  have todo with it... but this did not yet work out (only had access to one machie today, but still it lost connections)....
I will be in early tomorrow so before everyone arives I will have the machines properly set up (with autodisconnect to high values).
The workaround still is that mapped drives (i think that is the english term) STILL  ARE accessible even if the browser doesn't see other computers...... I think it is weird but is somehow congruent with what I stated before (I think)....

I keep you updated...thanks sofar

LVL 23

Expert Comment

by:Tim Holman
ID: 6500061
Sounds like there is some dodgy equipment on your LAN.
If the WINNT boxes are connected DIRECTLY to the switch, check with the switch that they come up as 100Mbs.  If not, force them to.
The switch may even be faulty...
Also check things like network printers, old hubs, but remember that new equipment does not necessarily mean properly working !

Author Comment

ID: 6505128
Well it was was all working for several days but now I am disconnected (browserwise). Still all mapped links work fine.... I'll live with that for a while until I have a little more time. Registry changing did apparently NOT work in the end.....


LVL 79

Expert Comment

ID: 7803773

This question appears to be abandoned. I will allow one week before I close this question
with the following recommendation:

- points to mikecr

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Author Comment

ID: 7819597
well it helped a bit but was not completely solved. this i did myself by reinstalling parts of software etc.

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