Hi All,

We have a small network in the office with 6 computers and couple of printers.

All machines are XP with individually assigned IP addresses.

We save all of our project data on one main machine which is then backed up
every day.

The problem we continue to have is that we lose the network path to this
main computer a couple of times a day (network path not found).  If we
restart the main machine all is well again until the next time it happens.

Can anyone please suggest a method to resolve this issue?

Thanks in advance.
Buster

Hi Buster

1) Is the main machine a server or is it as a multi task machine, server
functions and usual workstation stuff ?

2) What OS is installed in the Main Machine...2000, XP, Linux, Unix, Windows
2003 Server...etc ?

3) Is the network of 6 computers on a closed circuit not connected to the
Internet ,only a LAN or are the computers able to access the internet ?

4) Is the network setup with a Router or Switch ?

Thanks for the quick response!

Multi task machine

XP SP2 for all machine including the main.

The network is LAN connected to an ADSL modum

Router.

Hope that this helps.
Buster

Your main machine / storage pc is the computer that is causing all your
network not found issues. These types of issues can sometimes be a simple
thing that's causing it or it may be a more in depth issue with packets being
bounced because of a certain lack of configuratoin in XP.

A suggestion is to scrap the ADSL modem. I would imagine its a rental from
your ISP. First call your ISP and find out if you are able to use your own
bought DSL Router on their network without having to use their modem. In some
cases their configured modem might have some capabilities for diagnostic
reasons in tracking network congestion and any technical problems. You should
be able to use your own DSL Router directly.

  Your office should dish out a couple of coins to buy a DSL Router with
enough ports to jack in all computers.  Im guessing your current router may
have 6 ports the 6th port being a WAN port or a link up port to connect
another sub network router. Perhaps buy a 10 or more port DSL Router for
future expansion in your company.  In purchaing a DSL Router or a 2 in 1
Router which supports DSL & Cable connections. In case sometime down the road
you would like to hop over to cable.

Do some research on the different types of Classes of Routers. Making sure
it has all the bells and whistles. With all sorts of features in the
firmware, Security, DHCP, NAT, WEP and a bunch more of configurable features
to tweak for your Office LAN.

Your setup of having an ADSL modem connected to the router might be
simplified by simply buying an ADSL capable router. Where you can jack in
your tele cable directly to router eliminating a hop from the router to the
modem.  More hops may be added troubleshooting.

Purchase some type of server OS that can manage your main machine as
strictly a storage server. Something like Linux Redhat or Mandrake with GUI &
command line interface. Installing only the necessary services that you need
like perhaps a FTP storage server service.  Maybe a Microsoft server product
might do.

Okay... on to some troubleshooting suggestions...whew.

1)Open the coomand line Type  ipconfig /all  on all your computers making
sure node type is Broadcast. Make sure all windows firewalls are not blocking
ARP broadcasts or DHCP packets.

2) Enter IP and server IPs manually for each computer in TCP/IP settings..
Computers IP, Gateway IP give it a metric of 1, DNS Primary and
Secondary...For some strange reasons by having DNS or Gateway set to
automatic at times the auto settings loses it way. Had that happen many times
so I always manually entering Gateway & DNS settings.

Try these suggestions and hopefully this helps your 1 computer from dropping
its line from the rest of the group. I do have more suggestions if this does
not help.

Cheers !

Thanks for the help marbles.  I'm not real good at networks but eager to learn!

Just a couple of questions please:
1.  The mode is unknown so how do I change that?

2.  I know how to get to the firewall but don't know how to check re the
blocking of  ARP broadcasts or DHCP packets.

3.  All IP's are manual as I know about the auto problem.  Howeer, not sure
what you mean by "give it a metric of 1, DNS Primary and Secondary"

Thanks again.
BTW, are you English?  I am so use "cheers" which is very english.

Good Morning Buster

That's excellent..eager to learn..a positive outlook at learning !

1) Try this resolution - http://support.microsoft.com/kb/310570
to open registry editor start>run> type regedt32

if the above solution does not work then also try this resolution:

open registry editor start>run> type regedt32

Enter this registry parameter

Navigate to this tree folder
Key:HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Netbt\Parameters
right click in right pane window... new>Dword Value> Value name is NodeType
then right click on the new entry NodeType >modify enter 1 as the value.
This uses stritcly Broadcasts.

NodeType
Key:HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Netbt\Parameters
Value Type: REG_DWORD - Number
Valid Range: 1,2,4,8 (B-node, P-node, M-node, H-node) *
Default: 1 or 8 based on the WINS server configuration
Description: This parameter determines what methods NetBT uses to register
and resolve names. A B-node computer uses broadcasts. A P-node computer uses
only point- to-point name queries to a name server (WINS). An M-node computer
broadcasts first, and then queries the name server. An H-node computer
queries the name server first, and then broadcasts. Resolution through
LMHOSTS or DNS follows these methods. If this key is present, it will
override the DhcpNodeType key. If neither key is present, the computer uses
B-node if there are no WINS servers configured for the network. The computer
uses H-node if there is at least one WINS server configured.

2) Arp broadcasts uses ethertype hardware id 0x806 if your using windows
firewall most likely it's accepting it ARP. I use another firewall and not
familiar with the windows firewall. It might be resourceful to do research if
windows firewall does have the capability to block arp. You might try typing
a search key word on the microsoft website.

3) A metric of 1 is for the gateway entry. 1 is the lowest metric which
translates to using the shortest or fastest route available for Gateway.

Control Panel>Network Connections>Lan Connection..right click...properties
or double click...>properties again> Internet ProtocolTCP/IP
Settings...double click or select properties > bottom right click advanced >
Gateway click add ..enter the gatway ip and uncheck Automatic metric enter 1

4) When you ask english, do you ask as in British heritage ?

Hi Marbles,

OK I'll try that lot.  We seem to have a mixture of node types from unknown
to mixed. 

I'll get back to you once I have had time to go through it all.

Re English, I'm actually English but live in Sydney and use Cheers a lot as
most english people do.

Cheers!
Buster

Hello Buster

Ok sounds good...let me know the results when you have all the nodes changed
over to broadcasts in the registry setting... NodeType 1 ...hope it helps
...note after any registry change remember to restart computer.  Some changes
to the TCP/IP stack require a restart before the change can take effect.

Sydney Australia..oh nice ! I have been wanting to take a vacation to
Australia. When I save up enuff coin, perhaps then I can take that vacation.

I am Canadian... lived in the Province of Ontario for a good part of my
life. For the last couple of years I reside in Western Canada...Alberta.

Cheers is a great word to use ...simple yet effective in saying a friendly
hello,congrats,greetings or goodbye. A word that is timeless.

Have a good one !

Hi Marbles,

I've now changed all of the computers to broadcast and yep they seem to be
networking much quicker.  I haven't changed any of the IP addresses yet,
thought I would go one step at a time.

We have the following:

                           IP Address   Subnet              Defaulty Gate
Main Machine       10.0.2.67      255.255.255.0   10.0.2.60
2 Machine            10.0.2.81      255.255.255.0   10.0.2.60
3 Machine            10.0.2.83      255.255.255.0   10.0.2.60
4 Machine            10.0.2.62      255.255.255.0   10.0.2.60
5 Machine            10.0.2.66      255.255.255.0   10.0.2.60
6 Machine            10.0.2.76      255.255.255.0   10.0.2.60
7 Machine            10.0.2.65      255.255.255.0   10.0.2.60
8 Machine            10.0.2.61      255.255.255.0   10.0.2.60
Printer 1              10.0.2.71     
Printer 2              10.0.2.74     
Printer 3              10.0.2.73
Network Storage  10.0.2.75   

Should I change any of this lot although I'm not sure how to do that with
the printers.
Cheers
Buster
PS  Sydney is brilliant and well worth the trip and money!

Good Morning Buster

Examing the IPs and Subnets. They look to be fine. For printer IP's Im not
entirely sure. You might check your network connections folder or printers
and faxes folder located in the control panel. Look for the network printers
icon then click properties. The printers properties page might have a
configuration to allow you to change the IP address of the network printer.
You could leave it as is for now.

Before changing anything else. Let the networked computers run for a day and
see if your computers still drops connections. Let me know the results of the
network.

Then if they still are dropping network connections. The next step would be
looking at the router and dhcp settings, manual IP settings and a variety of
other configurations.

Have a good one !

Should have mentioned in the previous post it's interesting on the default's
gateway IP.  Most gateway IP addresses are something like 10.0.2.1  ..  1 is
the default or reserved number for gateways. Thou its not entirely necessary
because routers allow you to give it a custom IP. As long as your computers
recognize the routers custom IP and you remember that router ip address.

Default Gate
10.0.2.60

Worse case scenario would be the network totally loses it connection.  When
you do an " Ipconfig /all " from the command prompt. All Ip's list as empty
even your gateway / routers IP. If you don't remember the routers IP that was
given. You will have a tough time connecting to the routers firmware to
troubleshoot.  The easy way would be to reset the router. Then when resetting
the router, you lose all custom configurations in the firmware. That would be
the long way to fix a network going down the tube. The likely of this
happening is a small percentage.

A good thing to do is to write down the IP address of the gateway and put it
in a safe place in case the network does happen to do such a thing.

A tip... if this does happen, resetting the router would be used as a last
option. Instead download a good packet sniffer program from the net. Keep it
on a computers hard drive. Then when something like this happens.
1) Unplug the routers power supply.
2) Install the packet sniffer program.
3) Run the packet sniffer program when this is running then...
4) Plug the routers power supply back in...then
your packet sniffer program will capture the ARP broadcast IP of the router
and there you have it. Saving you from resetting the router and losing custom
configurations.

Cheers!

Hi Marbles,
Thanks for all your help.  W'll test it for a couple of days to see how we
go and I'll let you know.
Cheers
Buster

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Hello Buster

Hopefully this will be the configuration to correct the network problem...If
not, there is lots more options to try and correct the connections being
dropped.

Cheers !

Hi Marbles,
Unfortunately that didn't solve the problem :( although on the machines that
work they are quicker on the internet and networking so it was helpful to do
the things you suggested.
It seems to be something to do with the main machine as all other machines
continue to talk to each other but the main machine loses it's network
connection including internet of course.  Everyone else can get network
connection and the internet when it can't.
We also notice that it can take ages for one machine to connect to another
sometimes but that might be a different problem.
So far I have installed fixed IP addresses and changed the ModeType to
Broadcast.
So, where to now batman!
Cheers
Buster   

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Good Morning

Let's take a look at some areas that may cause path not found.

1) Do you have Service Pack 2 installed on the machines ? If not ..visit the
Windows Update web page. open Internet Explorer >Tools pull down menu Windows
Update and install all updates

2) What manufacturer made your ethernet card..D-Link, RealTek...etc ? Visit
the manufacturers website and download the latest patch/driver for your model
of ethernet card. Then install it ...reboot. Some ethernet network cards are
known to cause this issue.

3)Make sure the Server service is set to Automatic and is running.

4)Control Panel >System>Hardware Tab>Device Manager>under Network Devices
select your Network Adapter...double click or right click properties Look for
a Tab named Power Management or sift through the different tabs and look for
a option that says "Allow computer to to turn off this device for power
saving". Make sure this option is not checked marked.

5) Control Panel > Network Connections > double click you LAN network
connection >properties> uncheck Notify me when this connection has limited or
no connectivity

6) Interesting Article - http://support.microsoft.com/kb/320819

7) By Default windows XP limits Max. TCP connections to 10 at one time.
Previous versions of the Windows OS 2000 and before, allows unlimited TCP
connections. Since your using XP as a replacement for a file server with tons
of network traffic. This could cause some slow downs and back ups. Lets do
some heavy duty configuration and unlock the TCP max connections from 10 to
100 and add hardening the TCP/IP stack by invoking SynAttack protection on
your computers.

Enter these settings on your main machine. If you are satisified then try
entering these options on the rest of your computers on the LAN.

Open your registry editor >start>run>Regedt32 ...add the following 4
registry settings.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\parameter
Right click right window pane .. New > Dword Value> TcpMaxHalfOpen >right
click on the new entry...modify > Under the Base heading select Decimal>
Value Data enter 100..click ok.

Description: This parameter controls the number of connections in the
SYN-RCVD state allowed before SYN-ATTACK protection begins to operate. If
SynAttackProtect is set to 1, ensure that this value is lower than the AFD
listen backlog on the port you want to protect(see Backlog Parameters for
more information) . See the SynAttackProtect parameter for more details.


....next entry

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\parameter
Right click right window pane .. New>Dword Value> SynAttackProtect >right
click on the new entry...modify > Value Data enter 2..click ok.

Description: Synattack protection involves reducing the amount of
retransmissions for the SYN-ACKS, which will reduce the time for which
resources have to remain allocated. The allocation of route cache entry
resources is delayed until a connection is made. If synattackprotect = 2,
then the connection indication to AFD is delayed until the three-way
handshake is completed. Also note that the actions taken by the protection
mechanism only occur if TcpMaxHalfOpen and TcpMaxHalfOpenRetried settings are
exceeded.


entry#3..

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\parameter
Right click right window pane .. New>Dword Value> TcpMaxHalfOpenRetried
Decimal> Value Data enter 80..click ok.

Description: This parameter controls the number of connections in the
SYN-RCVD state for which there has been at least one retransmission of the
SYN sent, before SYN-ATTACK attack protection begins to operate. See the
SynAttackProtect parameter for more details.

4th entry...

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\parameter
Right click right window pane .. New>Dword Value> TcpNumConnections
Decimal> Value Data enter 100..click ok.

Description: This parameter limits the maximum number of connections that
TCP can have open at the same time. Even thou you could allow unlimited
amount of TCP connections with this setting. I have read postings on having
more then 100 simaltanious TCP connections may cause XP to slow down or cause
Operating System corruption possibly leading to the blue screen monster.

Whew.. ok try all of these suggestions and let me know how it goes.

Have a good one Buster !

Hi Marbles,

1) Do you have Service Pack 2 installed on the machines ?
    Yes
2) What manufacturer made your ethernet card..D-Link, RealTek...etc ? Visit
the manufacturers website and download the latest patch/driver for your
model
of ethernet card. Then install it ...reboot. Some ethernet network cards are
known to cause this issue.
    Will do.
3)Make sure the Server service is set to Automatic and is running.
   Yes and it was already on auto. 
4)Found that the computer was allowed to turn off the network card to save
power so turned that feature off.
5)Limited or no connectivity now truned off.
6) Interesting Article - http://support.microsoft.com/kb/320819
   Beyond me :(
7)JUst going to hold on the registry changes to see if the above has helped
first so that I know what has caused the problems.

Thanks for all your help and I'm off North for a couple of weeks so will get
back to you in the new year.  I wish you are yours the very best for
Christmas!
Paul

About helping you out..no problem Buster. You have done well and with the
right attitude in learning.  In learning computer systems we all start off
from the same point. The key is the willingness to learn.

Joyeux Noël et Bonne Année.. translation ..Merry Christmas and a Happy New
Year !

To you, your family and friends...Enjoy your holidays...!

In case you dabble in to the fruits of nature over the Holidays.
Aka..Alcohol and drink a bit too much..Hang Over Remedy....Water...lots of it.

Have a good one Buster we will chat in the new year !


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Just a reminder... Remember to restart the computer after you have entered
the 4 registry settings mentioned in the previous message.

Cheers!

Hi Buster

Did the new settings help ?

Cheers!

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