Understanding VMWare networking

Discussion in 'Virtual and Cloud Computing' started by flex22, Oct 27, 2004.

  1. flex22

    flex22 Gigabyte Poster

    Ok so we have 'host only' adapter.
    This allows the host system to commumicate with the guest operating system, correct?
    You still need to set them up in the same workgroup though don't you (if it is a workgroup)?
    So this 'host' adapter is actually the hosts, it belongs to the host and doesn't reside on the guest virtual machine, correct?
    If so, where does the virtual machine get it's adapter from, because each machine on a network needs a network adapter correct?

    So far I've just built small networks with VM but have somehow managed to share resources.
    I've not don things such as looking at the structure of the IP scheme etc.

    Instead of asking all my questions in one go, I'll just post the above about host adapter first, then build from that.

    Must admit that I'm a bit confused about VM networking at present, so will be glad when I've got a clearer representation in mind.
  2. nugget
    Honorary Member

    nugget Junior toady

    I wish I could help you here flex but it's the same thing bugging me. I'm also very interested in an answer.:oops:
    Certifications: A+ | Network+ | Security+ | MCP (270,271,272,290,620) | MCDST | MCTS:Vista
    WIP: MCSA, 70-622,680,685
  3. Phoenix
    Honorary Member

    Phoenix 53656e696f7220 4d6f64

    your confusing the modes a bit flex

    allow me to iterate

    perhaps you had your own small LAN, as i know you do (did) with a Laptop and a Server
    the subnet you use is perhaps

    VMware machines by default use Bridged networking, this basically means they are attached to this subnet
    and can collect DHCP address from say, your dhcp server, and route to the network the same way you do

    the network adapters are VIRTUAL, like every other component on the virtual machine, so we need not concern ourselves with that, what we need to understand is the way that network card interacts with the rest of our network

    a Bridged Connection:
    this basically assumes the device is part of your Local Area Network, it can communicate with anything on the same subnet, your other pcs, your router, and hence your net connection
    this is the DEFAULT mode for new VMs unless you specify something else..

    Host Only
    this is a bit confusing
    what this does is install another network card on your own machine (the host machine) which is virtual, you dont physically have that many network cards do you? and it assigns it an address in a DIFFERENT subnet to the rest of your LAN, say

    this network CANNOT interact with all the other machines on your network, but it CAN connect with the host machine because a second network card has been installed
    basically this is so you can set up self contained networks, that dont mess up your own network, and it can increase security by making them inaccessable to the outside world

    for small networks and vm configs, bridged is fine, easiest to use, and does what its supposed to do

    for more complex setups, as you may of seen in my diagram, we use seperate networks (host only, meaning the host can still communicate) and route that traffic as we see fit, until eventually its routed to a BRIDGED interface, and can hence access our network

    my file server for instance, can ping my virtual network, 4 subnets away, because there are routers handling the routing as part of my VM Lab

    you need a basic grasp of networking to understand this really
    bridged means they become part of the subnet you are currently using, so no clever stuff is required

    host only uses different networks, so routing WOULD be required, but an extra network card is installed on the host OS to allow IT and ONLY IT to communicate with that virtual network

    i know i didnt explain that as best i could
    ill try improve it if it makes no sense what so ever :)
    Certifications: MCSE, MCITP, VCP
    WIP: > 0
  4. flex22

    flex22 Gigabyte Poster

    Ok, I get that.When you say ‘and can’ do you mean they actually do use the DHCP on the LAN over the DHCP server in VMware.Probably answer is yes, but I just want to be absolutely right on with everything here.

    Is this an actual adapter, or is it a bridge? Like a bridge in the real world isn’t an adapter is it.It’s a physical thing isn’t it, like a hub type device, or is this more a logical term in this case.Does bridge connection in VMWare mean an adapter on the virtual machine that’s seen by the physical network or does it mean a device between the virtual machine and the physical real network.

    I just don’t want to go down that road for the time being.

    I get that no problems.
    I’m not getting this.Well I sort of do but I don’t.Firstly,
    can you can distinguish between physical and virtual network at all times.
    Here’s what I don’t get, I already understand what a host only network does, but doesn’t every machine on a network need a network adapter card in order to communicate? So if you have two machines they both need a network adapter card?Surely that is correct?
    Given that, your saying the host can now communicate with the virtual machine because it has a host only adapter.Again that’s clear to me.
    But what in the hell:!: is the virtual machine using to communicate with the host???????????

    Well I do, so carry on.
    Ahh that’s a shame, coz we’re all really clever around these parts.

    I’ll leave it their, because as I stated before, I want to take one step at a time to really understand this

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