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Intermittent Server Access / Network Connectivity Issues - Loss of Mapped Drives, Pri

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  • Intermittent Server Access / Network Connectivity Issues - Loss of Mapped Drives, Pri

    Very confusing one here, so I hope you have the patience to read as I'd really appreciate the help. Seems to even have Microsoft confused.

    Windows Server 2003 / XP Pro Environment.

    Servers Involved(?)



    ================================================== ==========

    -Intermittent disconnection from Network Drives on Server1:
    --Network Drive Monitoring App: "Local Device Name already in use"
    -Database Hangs - Local Client app, DB on Network Drive (on Server Server3)

    -Explorer hangs when opening, saving files etc -Primarily on two PCs/Users - but this seems to be as these users are a little more tech savvy and check explorer when other apps hang rather than just waiting:
    --Client1 (User1)
    --Client2 (User2)

    Loss of Database access/connection can occur on any machine. (Database stored on Network share on server Server3)

    When Server1 Shutdown:
    -Outlook Offline & Access to Database(on Server3) unavailable.
    --(Authentication/DNS should be handled by other Domain Controller Server2 ??)
    -NTP Errors in System log on Server2 (secondary DC) during shutdown - unable to locate an authoritative Time Server.

    Client3 Intermittently unable to connect to Exchange.
    ================================================== ==========


    -Upgraded NIC Drivers on Server1 (Requested by Microsoft). Re-teamed.

    DNS was referencing 3 former DCs in Name Servers list of both servers:
    -Server6(used during an upgrade, no longer exists at all)
    -Server4(exists only as a Proxy now)
    -Server5(no longer exists)
    --Removed these, Scavanged Stale Records, Cleared Cache.

    Verified DNS SRV DC Records according to MS KB

    Constant PING with Date stamp shows no response during disconnection time on Client1 Machine.
    Disconnection time not always uniform - no disconnection on Client2 machine during some of disconnections on Client1.

    No event logs of interest on Server1 or Server2 at times of Failures

    User1 & User2s' User A/C's in separate OU. Unlinked Logon GPO listed(User Configuration contains Logon Script but User Config disabled). Deleted from OU.

    Removed & re-added machine Client1 to Domain. Noted a few Explorer & other errors on this machine while logging in/working with it.
    Seemed to provide temporary relief on this machine - no errors for half day after this, though then re-commenced.

    An MS Technet case was opened and the following KBs Implemented/verfied, though with no improvement: - DNS Connections limit. - Type of "Heartbeat" between client & server to aid maintenance of network drive connectivity.

    Users are also reporting loss of connectivity to Network Drives on Server4 and Server3. Applications the database for which are on Server3 intermittently hang but I think this is usually when users attempt to print as printers are installed on Server1.

    -Switches and Network Cables have been swapped out. Direct to swtich cabling has been tried (to rule out cabling issues in walls).

    -Machines have been scanned for viruses (though are using RealTime protection anyway.

    -Machines have been re-tested without any AV installed also.

    ================================================== =====

    Pulling our hair our here so any help appreciated. Microsoft are trying little TCP registry tweaks but I'm suspicious its something more obvious/bigger.

    Next step is to go in out of hours and isolate the servers and 2 or 3 client machines (total of about 20) on a single switch and disconnect all other clients from this switch to see if issue persists.

  • #2
    Re: Intermittent Server Access / Network Connectivity Issues - Loss of Mapped Drives,

    Analyse the traffic on the network and try a different switch/isolate machines as you have mentioned yourself.