Networking Problems - Host to Guest And Guest to Host...

Discussion in 'Virtual PC' started by RRBILLY, Sep 11, 2004.


    RRBILLY Guest

    I have a W2K Pro Desktop (Host) and have installed Win 2003 Server Std.

    The problem is intermitent - The Host has a Asus [email protected] 802.11 NIC in
    it and the Guest has by default installed: Intel 21140-Based PCI Fast
    Ethernet Adapter (Generic). The wierd problem is that both Host and Guest
    can access the internet with no problems, however they are only visible via
    and ICMP Ping from time to time. It works and then stops. Over and over...
    So they can both communicate to the outside world with no issues, but can
    not talk to each other. My goal is to run IIS/Sharepoint on the Guest and
    access it from the Host via IE, but it will not work on the private IPs that
    are currently set up.



    Again, both can access the internet perfectly with not real issues, but they
    fail consistently to talk to each other - Please help!

    Thank you,

    RRBILLY, Sep 11, 2004
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    007 Guest

    if u can see internet on other computers then this means there is no trouble
    with hardware and ICS is enabled. there should b some settings needs
    changing. now check if both computer are on same workgroup.
    right click mycomputer -> click properties-> go to "computer Name" tab->
    click change button and have a look they both are on same workgroup. after u
    have done that then share some folder and see u can see on both computer... i
    hope this helps.
    007, Sep 12, 2004
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    Bill Grant Guest

    All sorts of odd problems come up if you use wireless NICs. I can't ping
    from host to guest (or vice versa) using my wireless NIC. Works fine using
    the Ethernet NIC or the loopback adapter.

    I would suggest setting up a loopback adapter on the host and using that
    to communicate with the guest, rather than the wireless NIC.
    Bill Grant, Sep 12, 2004

    RRBILLY Guest

    Thank you for the reply...

    To clarify - I can not ICMP ping host to guest or guest to host - well I can
    now and then but not consistently. I change the IP and it works for awhile
    and then stops again...

    RRBILLY, Sep 12, 2004

    Steve Jain Guest

    This is probably indicating that your wireless card's drivers are
    working correctly and attempting to prevent MAC spoofing.

    Try with a regular wired NIC and that will probably resolve your
    issues. Or, you could use the MS Loopback adapter and ICS to bridge
    to the wireless NIC.

    Steve Jain, Microsoft MVP for Virtual PC for Windows
    *** All posts are provided AS-IS, no warranty, no QoS ***
    Steve Jain, Sep 12, 2004

    Scott Baker Guest

    You need to provide the details of the _current_ Host and
    Guest configurations to make any meaningful response

    Scott Baker, Sep 15, 2004

    pml Guest

    Well the problem continues... I installed the loop back and still can not
    Which steps have you taken?
    - Install loopback adapter driver on *host*
    - Assign the address mask
    - (Shut guest down)
    - In VPC Console > Guest settings > Networking change Network Adapter to
    the Loopback Adapter
    (or say if it is not in the list; you may have to check the network
    binding properties)
    - (startup guest)
    - Start guest, change TCP/IP properties to address mask default gateway
    - (You might have to reboot guest)
    - Now, from the host, try to ping
    - From the guest, try to ping

    If you want internet connectivity from the guest, just enable Internet
    Connection Sharing on the host's network adapter that has the internet
    connection. You may have to check DNS server properties on the guest or set
    it to "use DHCP".
    pml, Sep 16, 2004

    RRBILLY Guest

    If I use the loopback, or the hardwired NIC, and try to add it to the same
    network ( as the WiFi adapter every configuraiton comes back
    with the same problem - they can talk to the gateway and the Internet, but
    Guest to Host & Host to Guest can not communicate. No ICMP, or TCP
    communications. However, every now and then it works for a few minutes and
    then dies again.

    From an ARP perspective the devices (however configured - and rebooted until
    the cows come home) all end up not in the ARP table. Again the goal is to
    get Guest to Host & Host to Guest to see each other and share resources while
    both have the ability to use the Internet...

    - Loopback did not work: Config - /28
    - Direct to WiFi did not work: Config - /28
    - OnBoard hardwired NIC did not work: - /28

    All seem to have the same problem.


    RRBILLY, Sep 20, 2004

    pml Guest

    You cant use the same network ( on two adapters on the same
    time on the same host. Make sure that the network numbers of the physical
    (ie wireless) and loopback adapter do *not* overlap.

    I recommend you using addresses (see my post below) on the
    "virtual" network (loopback adapter + guests) because then you can easily
    turn on Internet Connection Sharing to get the guests connect to other
    computers (with some limitations) & the Internet.
    pml, Sep 20, 2004

    RRBILLY Guest

    Ok - Let's run through it...

    Starting with the basics:

    Host (WiFi):

    No problems with network or access.


    Can connect to Internet through whatever virtual config I use - however can
    not connect directly to Host. After the Guest has booted and uses either
    WiFi (virtual), Hardwired (virtual), or Loopback; with the following

    Virtual Device:

    Does this help?

    RRBILLY, Sep 20, 2004

    Scott Baker Guest

    See pml's reply to your other posting.

    Scott Baker, Sep 21, 2004

    RRBILLY Guest

    Comments inline->

    Thank you for the advice so far, but can I ask why not? If two seprate
    physical, or logical, devices have IPs on the same network, how is that an
    issue? Two IPs - Two MACs - what am I missing?
    RRBILLY, Sep 21, 2004

    DevilsPGD Guest

    In message <e9p$> "pml"
    You can actually do this easily if they're physical adapters connected
    to the same physical network.

    However, putting one physical adapter and one loopback adapter in the
    same subnet would be bad mojo.
    DevilsPGD, Sep 21, 2004

    pml Guest

    Well, your approach *can* work, *if* you define ARP mapping manually and/or
    route individual IP addresses though a specific network adapter (by using
    the IF parameter in the route add command).

    The reason why its not (generally) possible is that when you set up the IP
    address and netmark for a network adapter, there will be an implicit route
    created for that network through that network adapter, and if there is two
    routes with the same metric, I guess the routing is kind of undefined and
    the OS may choose the first network adapter that is up, and the OS will make
    ARP broadcast on only that network adapter.

    You can see the routing table by using the command
    from the command line (cmd.exe in NT based OS:es; in DOS based
    pml, Sep 21, 2004

    RRBILLY Guest

    Well I do want to thank you for the advice... I ended up rebuilding the
    v-host onto the 192/24 network, as you suggested and it is up and running.
    Not enough time to do more now except for make this internet connection stuff
    work properly...

    Anyways thanks again... I think that if I do it over again I will ditch the
    ICS stuff and just add the routes...

    RRBILLY, Sep 22, 2004
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