Computers drop out of network

http://www.winguides.com/registry/display.php/194/

Change LAN Auto-disconnect Timeout (Windows NT/2000/XP)

Windows can be configured to automatically disconnect idle LAN sessions are a set number of minutes.

This tweak can be easily applied using WinGuides Tweak Manager.

Download a free trial now!

Open your registry and find the key below.

Modify the value, or create a new string value, called 'Autodisconnect' and set it to equal the time in minutes before a session is disconnected.

Restart Windows for the change to take effect.

Note: Set the value to 0xffffffff to disable the disconnection function.





(Default) REG_SZ (value not set)

Autodisconnect REG_DWORD 0xffffffff (4294967295)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanS...



Registry Settings

System Key: [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\

Parameters]

Value Name: Autodisconnect

Data Type: REG_DWORD (DWORD Value)

Value Data: 0 to 4,294,967,295 (0xffffffff) in minutes


Disclaimer: Modifying the registry can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from modifications to the registry can be solved. Use the information provided at your own risk

It could be.  What OS are your running?  Is anything showing up on the event logs when this happens?

One thing i forgot to add is ipconfig /renew doesn't work it just sits there.

Event Type:      Error
Event Source:      Dhcp
Event Category:      None
Event ID:      1002
Date:            1/8/2005
Time:            11:05:55 AM
User:            N/A
Computer:      SARAH-4
Description:
The IP address lease 192.168.1.102 for the Network Card with network address 000EA6143D85 has been denied by the DHCP server 192.168.1.1 (The DHCP Server sent a DHCPNACK message).

The semaphore timeout period has expired. . Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.

Your computer has lost the lease to its IP address 192.168.100.11 on the Network Card with network address 000EA6143D85.

here's what seems to be the problem.  
Event Type:      Error
Event Source:      MRxSmb
Event Category:      None
Event ID:      8003
Date:            1/9/2005
Time:            10:29:37 AM
User:            N/A
Computer:      SARAH-4
Description:
The master browser has received a server announcement from the computer MSI that believes that it is the master browser ...

 The master browser is stopping or an election is being forced.

But then you get an IP address ok when you reboot?  You may want to make sure your antivirus is updated and run scans on all your hard drives.  If that is good then do an ipconfig /all and post the result.  I'm curious if your lease time matches the times that you drop.

The master browser is just a means for your PCs to find each other via NETBIOS name - I don't think it has a bearing on why your DHCP addresses are not renewing.  What is the timeframe of the the DHCP messages you show above?

what is the dhcp lease time set for the router?
what make/model router is this?

If you haven't already, I'd do a firmware update on the router to make sure it wasn't somehow corrupted.

Wireless-G Broadband Router
   WRT54G
 
client lease time is set for 1 day in router settings.

Yes when i reboot everything is fine for the time being.

>>Yes when i reboot everything is fine for the time being
reboot the router or the machine?
the way the lease works is after 50% of the lease time, the client will ask for a renewal, if no response, then it will ask at 75% and then 87% and so on
you are getting a  DHCPNACK which meaqns the server said no
do you have mac address filtering set on this? what wep/wpa settings do you have?

>>reboot the router or the machine?
when I reboot the computer that isn't connecting.  

wep is set to 128 bit encryption, but i'm not even using wireless.  This is just happening with the computers cabled into the router.  

I got all 4 computers up right now on the network, i'm just waiting for it to happen on one of them again.  

I'll try to get  an accurate time and description of the error next time it happens.  Of course it won't happen probably because I want it too ;)

I think your DHCP table is mess up in the router.
Reset your router to factory setting and configure it again.

it's mainly just one computer that drops out of the network.  I've reset the router and i still get the problem.

could 1 computer cause this?

I got my network icons down by the clock with x's covering them but it still is connected, does this make any sense to anyone?

It would only make sense if you had more than one network card installed.  The one's that aren't plugged in would show up as the X.  The working connection would be up, but wouldn't be visible unless the "show  icon in taskbar when connected" box is checked in network connection properties. Can you check the DHCP leases on your Router and match them up to your PCs?  Are they any other DHCP leases other than the 4 PCs?