Workgroups and synergy

By rednek ยท 7 replies
May 3, 2010
  1. Hi
    I have 2 PCs (1 x XP Pro, 1 x XP Home), connected to our home network and the internet via wireless. However, I'd like to be able to wired connections, via a switch, to connect to each other, so I can run Synergy (where you share 1 keyboard and mouse) locally as opposed to going via the wireless home network - which glitches a little. Also I'd like to use LAN-based music software which is time-critical, via the switch rather than wireless.

    Is there a way to specify which software uses which network adaptor? Also is there a way to ensure file transfer from one to the other happens via the wired connection as opposed to the wireless home network?

    Many thanks in advance,
  2. jobeard

    jobeard TS Ambassador Posts: 11,128   +982

    This is known as a KVM a/b switch, where systems video, mouse and keyboard from two system attach to a KVB switch, where the real devices are also attached. The A/B switch is then used to select which system has the connection to the real devices.
    The 'right way' (imo) to share the Internet is with a common router, like this
    The alternative is to serialize the connections like this
    System#1 uses one NIC (or WiFi) to access the Internet via the router and then
    a second NIC (using Internet Connection Sharing) to access system#2.
    If that link is wired, then the traffic between the two will be at the 10/100Mbps of that link
    rather than the 54mbps of the wifi.

    It should be clear that The alternative requires BOTH systems running if system #2 is to have
    any Internet access at all and that System#1 will influence the performance of system#2
  3. rednek

    rednek TS Rookie Topic Starter

    Many thanks.

  4. jobeard

    jobeard TS Ambassador Posts: 11,128   +982

    btw; be prepared for an oddity; the wired nic attached to system using ICS *WILL* demand to have the address and thus system#2 will be something like 192.168.0.x

    this means that the WiFi connection to the Internet can not have 192.168.0.* anything
  5. rednek

    rednek TS Rookie Topic Starter

    Many thanks for your time and help joebeard.

    What I need to know is if there is a way to have system#1 and system#2 access the wireless router, and therefore the internet, via their wireless adaptors, AND access eachother via their NICs through a 10/100 switch; and to specify the fact that Synergy (the software KVM switch), together with my LAN-basd music software will use the WIRED connection not the wireless. Would this be achievable through subnet masking?

    Your second suggestion would get me nearly there, but as you say, I'd need for both systems to be on in order for system#2 to access the internet. System#2 is a laptop which I regularly use independantly of, and remotely from, system#1

    Kind Regards

  6. jobeard

    jobeard TS Ambassador Posts: 11,128   +982

    Not subnet mask, but by manipulation of the routing table in both systems.

    Recall, the wifi router needs to be at a different address than
    For clarity, let's say you set the router to have address
    Then we need two things to happen;

    a) all systems must use the routers address as the default route to make Internet access still available
    b) a special addition is made to both system's routing table to force communications
    between them.

    (a) is easy, but (b) needs to be done at every boot and if the laptop travels to work or hotspots, you will need to avoid the routing table update.

    So on the desktop system
    • route add default
    • route add
    while on the laptop
    • route add default
    • route add

    notice the desktop change to point at the laptop and conversely for the laptop

    The above is conceptual and not the actual means to implement this and I don't have the time right now to document the settings and detailed how-to.

    If you want to try this, I'll work on it tomorrow.
  7. rednek

    rednek TS Rookie Topic Starter

    Thanks again jobeard.

    I would indeed like to try this out, it sounds ideal - other than the fact that it needs to be done for each boot. Although I guess I could write a script for that and put it in the startup directory?
    Kind Regards
  8. jobeard

    jobeard TS Ambassador Posts: 11,128   +982

    we can fix that when it's all correctly mapped.

    Step 1: get this configuration:
    with the wireless connection to the router. with that working
    (make sure your router is NOT at 192.168.01)
    get a command prompt and enter
    ipconfig /all >myINET.txt
    to document system#1 config

    Then wire #1->#2 using the NIC card
    using an Admin login on System#1
    Enable the ICS feature using the Network Connection(setup) Wizard
    and click the ( ) that contains ...'other computers connect ... through this computer'

    The system#1 NIC will now have an address of

    Now rerun IPCONFIG /ALL >myICS.txt from system#1

    and also show me the existing routing table
    netstat -r >myRT.txt

    when you follow-up, attach the files
    1. myINET.txt
    2. myICS.txt
    3. myRT.txt

    Without further changes,
    • system#1 should have full access to the internet
    • system#1 should be able to ping system#2
    • system#2 should be able to ping system#1
    • system#2 *may* or *may not* have internet access

    Please include which Firewall you are using on both systems
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