What is the difference between "bridged" and "shared" networking?

Discussion in 'Windows Virtual Machine' started by jjfcpa@mindspring.com, Jul 9, 2007.

  1. jjfcpa@mindspring.com

    jjfcpa@mindspring.com Member

    I've got a Novatel USB720 modem and it works fine with OS X on my Macbook Pro; however, it will only work on my XP vm in "shared" mode and not with the "bridged" network setting that I normally use.

    Can anyone explain the difference between the two and why bridged won't work, but shared will?
  2. mcowger

    mcowger Member

    Bridged mode exposes 2 mac addresses coming out of your ethernet card to the wire - that of your mac, and a separate one for your VM. As far as your network/modem is concerned, your computer looks like a hub/switch with 2 machiens connected to it. The benefit is that you can have 2 separate IPs and not worry about port forwarding, etc. for your VM.

    Shared mode makes your mac act like a router, and as such only 1 mac address is exposed to the outside world.

    The likely reason for the failure mode during bridged mode is that many DSL/Cable modems will only talk to 1 mac address on the client side at a time. When you have 2 addresses showing (as with bridged mode), only the first one to talk (your mac) get to talk at all.

    Unless you have a very specific need for bridged mode (e.g. you are testing DHCP, running a server, etc) in XP, shared mode should work fine for you.
  3. jjfcpa@mindspring.com

    jjfcpa@mindspring.com Member


    Thank you for the very informative reply.
  4. asterion

    asterion Junior Member

    Shared mode may also be the only way to get access at all for the VM if the network you're on uses DHCP. I've never been able to get bridged networking to work properly on a particular academic network, even when I specifically tried spoofing the MAC address.

Share This Page