local network drops out after some time for some pc only

Discussion in 'Server Networking' started by tom mitchell, Sep 11, 2004.

  1. tom mitchell

    tom mitchell Guest

    Situation: Local network with 4 pc
    PC A: Internet Gateway PC W2000 running Zone Alarm Pro
    PC B: XP recently installed SP2 and enabled inbuilt Firewall, changed
    to Kerio
    PC C: W98
    PD D: XP

    All are networked. Internet access works fine and initially the local
    network works fine too.

    Problem: After about 2 hours PC C is no longer able to see PC B.
    Checking via Network Neighbourhood it appears that PC B has
    gone/dropped off. Strangely enough, those files that are accessed via
    the "recently used file list " in Word or Excel or that have shortcuts
    on the desktop are still available. Using Explorer or open file in
    Word does not work. So in fact the connection is still there but just
    does not show up anymore, meaning saving files across is
    impossible.Also, the conncection from PCB to PC C remains normal.

    Once I reboot PC C, everything is back to normal until the next drop
    out.
    This only started since SP2 was installed and seems to affect both PC
    A and C. I thought it might have something to do with XP firewall but
    after disabling it and installing Kerio FW, the same problem is still
    occurring.

    Any idea how to fix this? Is this something I can adjust in the XP
    firewall?

    Any assistance is greatly appreciated.
    Kind Regards
    Tom

    Please post to this newsgroup
     
    tom mitchell, Sep 11, 2004
    #1
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  2. If you enable firewalls on the lan they can cause problems like you are experiencing.
    Most can be configured with trusted zones to allow traffic from network computers. It
    sounds like the browse list is being blocked which uses port 138 udp. If you have a
    cable/dsl modem you might want to consider using a NAT router/firewall to protect the
    lan and not use a gateway computer. XP SP2 has the ICF firewall enabled by default
    but you can configure it to allow an exception for file and print sharing and edit
    the exception so that the scope is the lan subnet. Otherwise you can just live with
    it an map drives instead of browsing My Network Places. --- Steve
     
    Steven L Umbach, Sep 11, 2004
    #2
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  3. tom mitchell

    tom mitchell Guest

    Steve,
    thanks for that.
    I don't think it's the firewalls as the local network is properly set
    up in Zones.
    However, mapping the drives seems to work.
    What exactly is the difference in accessing files via mapped drives
    instead of my network neighbourhood? Are there any security or other
    issues that I should be aware of?

    Kind Regards
    Tom


    Kind Regards
    Tom

    Please post to this newsgroup
     
    tom mitchell, Sep 12, 2004
    #3
  4. When you access shares via My Network Places you rely on the ability of the "browse
    list" as shown in My Network Places to find the shares. If the share can not be
    found, you can not make a connection without knowing the share server name or IP
    address. When you map a drive you bypass the browse list and make a direct connection
    using either netbios name resolution or dns host name resolution if you specify a
    computer name or you also can use the IP address of the computer to bypass name
    resolution which only works well for computers that don't have changing IP addresses
    such as DHCP clients without a reservation would have. If you have a properly
    configured firewall, up to date virus protection that scans all emails also, keep
    current on critical updates, and use complex passwords you should be in good shape
    security wise from internet attacks assuming you are careful in what you download and
    install on your computer.

    I find that browsing problems are usually related to firewalls or other IP filtering
    blocking access, master browsers having more than one nic, no current master browser
    on the network because the other computers can not be one [they all can by default],
    computers frequently being started up or shut down, browsing across subnets without
    wins or lmhosts files, file and print sharing not being installed, the server service
    not running, or netbios over tcp/ip is not enabled on a computer which Ipconfig /all
    will inform you of. Note that it can take up to an hour or so for a computer to
    appear in the browse list if the master browser is shut down. The command nbtstat -n
    will show if a computer is a master browser and give it's other current netbios name
    registrations. See the link below if you want to learn more about the browse
    service. --- Steve

    http://www.microsoft.com/resources/.../server/reskit/en-us/tcpip/part4/tcpappi.mspx
     
    Steven L Umbach, Sep 12, 2004
    #4
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