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How to Troubleshoot Network Connection Problems with Windows Home Server

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  • How to: Troubleshoot Network Connection Problems with Windows Home Server

    This FAQ attempts to describe some known reasons for network connection problems with Windows Home Server and give hints, how to solve them. Since home networking configurations may be very different and complex, not each scenario can be covered.


    Symptoms

    When you try to install the Connector software from CD, the shared folder \\Server\Software\Home Server Connector Software or the Website http://server:55000 the server cannot be found at some point. The same can happen at a later time, if you try to open the console from the context menu of the already installed Connector. The error messages may vary, they may look like Server not found, The operation cannot be completed at this time or Password incorrect.


    Causes

    The problem can be caused by various different reasons:

      A 3rd party security suite on the client may block the ports necessary for the communication between connector and server. (Possible solution: Uninstall the security suite.)
      The server and the clients are located in different IP subnets. (Possible solution: Connect the machines to the same network or disable the rogue DHCP server, if one exist additional to the router.)
      A router sends unnecessary or wrong DHCP settings to the client, causing name resolution troubles. (Possible solution: see below)
      A manual made entry in the hosts file is no longer valid. (Possible solution: Check the hosts file, remove or correct the faulty entry.)
      NVidia video card drivers on the server block Remote Desktop connections. (Possible solution: See FAQ How to handle error message “The Password is incorrect” attempting console access)
      Faulty network hardware or drivers.
      Multiple network cards in one machine (so called multihomed configuration).
      IIS misconfiguration on the server. (Possible solution: Check, if some application changed the ASP.NET settings in IIS to version 1.x instead of 2.x and  change this back)
      COM or DCOM components or permissions on the server altered by user or software. (Possible Solution: Check the event log on the server for related warnings and errors and try to fix those.)
      Power Save settings of the network adapter (Possible solution: Change on the Power Management tab of the network card in device manager)
      date/time and time zone differences between client and server

    Diagnostics
    Since the complexity and variety of home networks makes it not easy, to pinpoint the reason for troubles, some methods will be described, which should narrow down the specific problem.


    ipconfig

    The command ipconfig allows you, to read the IP configuration of network adapters in the command line. It can be necessary to execute the command on both the client and the server as follows (menus may differ depending from the operating system):

    ·         Open Start/All Programs/Accessories and click Command Prompt.

    ·         In the black window type the command

             ipconfig /all

    If you wish to post the output, click the System menu on the left side of the title bar, select Edit/Mark and mark the block with the mouse. Hit the Enter key to finish the marking and copy the marked text into the clipboard. From here you can paste the information into notepad or the forum posting window, so that the output looks similar like this:

    C:\Documents and Settings\Administrator>ipconfig /all

    Windows IP Configuration

       Host Name . . . . . . . . . . . . : MYWHS

       Primary Dns Suffix  . . . . . . . :

       Node Type . . . . . . . . . . . . : Hybrid

       IP Routing Enabled. . . . . . . . : No

       WINS Proxy Enabled. . . . . . . . : No

       DNS Suffix Search List. . . . . . : xxx.yyy.com

    Ethernet adapter Local Area Connection:

       Connection-specific DNS Suffix  . : xxx.yyy.com

       Description . . . . . . . . . . . : SiS191 1000/100/10 Ethernet Device

       Physical Address. . . . . . . . . : 00-0A-E4-85-DD-13

       DHCP Enabled. . . . . . . . . . . : Yes

       Autoconfiguration Enabled . . . . : Yes

       IP Address. . . . . . . . . . . . : 192.168.0.103

       Subnet Mask . . . . . . . . . . . : 255.255.255.0

       Default Gateway . . . . . . . . . : 192.168.0.1

       DHCP Server . . . . . . . . . . . : 192.168.0.1

       DNS Servers . . . . . . . . . . . : 192.168.0.1

       Lease Obtained. . . . . . . . . . : Tuesday, October 13, 2009 6:07:15 AM

       Lease Expires . . . . . . . . . . : Tuesday, October 13, 2009 6:07:15 PM

     

    The output may vary (so for Vista and Windows 7 you will see IPv6 addresses as well).

    This information helps, to find some of network configuration settings, which may cause Connector software to fail.

    Primary DNS Suffix, DNS Suffix Search List, Connection-specific DNS Suffix:

    In a home network these settings should be empty. If they are not, and if the value is a valid Internet Domain name (like many ISPs tend to configure), the router will take the name of the server, attach that suffix and query the DNS server of the ISP for resolution of the name. This will in each case fail, since the external DNS server cannot resolve your internal server, but the exact result may differ.

    If the DNS server of the ISP is authoritative for the domain represented by the suffix and not a server in this domain has the same name like your Windows Home Server, it could respond with a name resolution failed message. If it is not authoritative for the domain, it will try to find a DNS server, which is authoritative and can resolve a name in that domain. This can end with the same result, name resolution failed. After getting this message back, the client can either attempt to resolve the name via broadcast, or it already did run into a timeout. If the later, a repeated attempt may establish a connection successfully.

    But the DNS Server of the ISP can also return a wrong IP address – if either the server name exists in the Internet domain or if the authoritative DNS server returns a generic address for all unresolved names (i.e. the advertisement website for the domain hoster). In this case the client attempts the connection to this wrong address, which fails.

    Workarounds:

    Method 1: Removing the DNS suffix from the router

    Drawbacks of this method: not always applicable, depending from the router/ISP

    You will find the domain given as suffix usually somewhere in the routers configuration interface. It depends from the model and the ISP, if you can successfully remove it. If you cannot remove it, but alter the value, try a single label name, i.e. Workgroup. These are not resolved through the Internet. After that at least a reboot of the client and the server are necessary. If the suffix still is stuck in the configuration, you may have to renew the IP address on the client. To do this, open a command prompt (on Vista/Windows 7 as Administrator) and enter the following commands:

    ipconfig /release

    ipconfig /renew

    Method 2: Configuring manual IP addresses on all clients and the server

    Drawbacks of this method: typos may cause connectivity issues, later changes of the router hardware may leave the machines disconnected, time consuming

    If you cannot figure out, how to remove the DNS suffix from the router, or if the router stops to connect to the ISP, if you do so, it may be useful to configure manually IP addresses, subnet settings, default gateway and DNS server on each machine. Stay in the same subnet (i.e. 192.168.0.xx) as the router did offer, but stay outside of the address range the router reserves for DHCP (you should be able to see this range in the configuration of the router). As default gateway and DNS server use the IP address of the router. How to configure the IP address manually, should be documented in the Help files of your operating system.

    Hint: If you change the IP address of the server as well, be especially careful on headless machines, since each typo will end in a necessary server recovery.

    After altering the servers IP address in that way, you will have to run discovery.exe in C:\Program Files\Windows Home Server on each client PC to reestablish the connection.

    Method 3: Alter the hosts file on each client

    Drawbacks of this method: static assignment of IP address will often be forgotten overtime and so cause connectivity issues, if the server changes the IP address (due to a router reset/hardware change or a server reinstallation)

    The hosts file is a text file without extensions, which can be found in the folder C:\Windows\system32\drivers\etc. If you want to edit this file in Vista or Windows 7, open Notepad as Administrator from the context menu in its shortcut. In Notepad click File/Open, navigate to the mentioned folder, select All Files (*.*) instead of Text files and open the file hosts.

    It looks like

    # Copyright (c) 1993-2006 Microsoft Corp.

    #

    # This is a sample HOSTS file used by Microsoft TCP/IP for Windows.

    #

    # This file contains the mappings of IP addresses to host names. Each

    # entry should be kept on an individual line. The IP address should

    # be placed in the first column followed by the corresponding host name.

    # The IP address and the host name should be separated by at least one

    # space.

    #

    # Additionally, comments (such as these) may be inserted on individual

    # lines or following the machine name denoted by a '#' symbol.

    #

    # For example:

    #

    #      102.54.94.97     rhino.acme.com          # source server

    #       38.25.63.10     x.acme.com              # x client host

     

    127.0.0.1       localhost

    ::1             localhost

     

    For the Windows Home Server add a line on the end, for the example configuration above would this be

    192.168.0.103  MYWHS

    Close Notepad and save the changes.

     

    Node Type

    This is often set to Unknown. Especially modern operating systems like Vista and Windows 7 rely on name resolution via DNS and do not use the old method via NetBIOS any more by default.

    To enable name resolution via NetBIOS, you can open the TCP/IP configuration of the network adapter on all clients and the server.

    Click the Advanced button, select the WINS tab, click the radio button Enable NetBIOS over TCP/IP and confirm the change.


    IP Address

    The first digits of the IP addresses on the client and server should match (in the example above 192.168.0). If this is not the case, the machines are either in different subnets or misconfigured.


    Subnet Mask

    This should be identical on each of the machines.


    Default Gateway, DHCP Server and DNS Servers

    In a normal home network environment these entries should be identical and point to the IP address of the router. Sometimes the DNS servers of the Internet Service Provider (ISP) are directly listed here, which leads to the same effects as the wrong DNS suffixes.


    Lease obtained/Lease expired:

    If this DHCP setting is too short configured, the client needs to renew its IP address very often. This may cause problems during a bare metal restore of a client using the Restore CD. If this setting can be changed, this is possible only in the routers own interface.

     

    Other helpful diagnostic commands

    ping

    The ping command sends a packet to the server and gets an answer back. In a command prompt you enter

    ping servername (replace servername with the name of your Windows Home Server)

    to attempt a ping to the server by its name. If it works, you will see lines similar to

    Pinging MYWHS [192.168.153.103] with 32 bytes of data:

    Reply from 192.168.153.103: bytes=32 time<1ms TTL=128

    If this fails or the reply comes back from the wrong IP address (usually one in the Internet), try to ping the server by its known IP address:

    ping 192.168.0.103

     

    nslookup

    This command shows the DNS server configured for the client. If you enter the name of your Windows Home Server in the appearing prompt, that DNS server should either respond with the internal IP address or the server or not find the server. If the address listed is an external, this is the reason for the failing connection attempts. You can leave the nslookup prompt with the command exit.

     

    nbtstat

    This command allows to validate NetBIOS name resolution (which is of interest, if the shortcut Shared Folders on Server does not work).

    A command like

    nbtstat –A 192.168.0.103 (replace the IP address with the known IP address of your server)

    should return something like:

    Local Area Connection:

    Node IpAddress: [192.168.153.111] Scope Id: []

              NetBIOS Remote Machine Name Table

          Name               Type         Status

       ---------------------------------------------

       MYWHS          <00>  UNIQUE      Registered

       WORKGROUP      <00>  GROUP       Registered

       MYWHS          <20>  UNIQUE      Registered

       WORKGROUP      <1E>  GROUP       Registered

       WORKGROUP      <1D>  UNIQUE      Registered

       ..__MSBROWSE__.<01>  GROUP       Registered

     

    If no result is listed here, NetBIOS network connectivity may not be given (or you attempt to use the wrong IP address). Many routers allow you to show, to which machines they assigned IP addresses or did allow connections.

    Multihomed machines
    A multihomed machine is a PC (client or server) with more than one network adapter. This can be real network adapters, but also FireWire or Bluetooth interfaces, a modem etc. Such configuration can end in communication attempts through the wrong interface.
    To fix this, you can either disable all unnecessary interfaces or try changing the priority.
    In Windows Home Server/Windows XP open Control Panel/Network Connections, in Vista/Windows 7 open the Network and Sharing Center and click Change adapter settings.
    Open the menu Advanced/Advanced settings.
    On the Adapters and Bindings tab move the wanted network connection to the top and click OK.


    Best greetings from Germany

    Olaf

    martedì 13 ottobre 2009 12:52
    Moderatore