Confusion about Virtual Adapters and General Network Setup

Issues related to configuring your network
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Edelweiss675
Posts: 1
Joined: 2015/03/04 23:29:03

Confusion about Virtual Adapters and General Network Setup

Post by Edelweiss675 » 2015/03/05 00:24:01

Hello all,
I am trying to setup a specific network configuration on my CentoOS 6 OS. I'm running into some issues that I don't quite understand and could use some help understanding them.
I am running Centos on a virtual machine hosted on a Mac. I use VMWare Fusion.

From my experience trying to do this, I am confused in a number of areas.
  1. How is the network managed?
    1. I know that /etc/init.d/network does some of it. However, when I created the ifcfg file under /etc/sysconfig/network-scripts/ifcfg-eth0:0, "service network restart" does not bring up the virtual adapter. Interestingly enough, when I restart the VM, the virtual adapters are up.
    2. I notice there is a utility called NetworkManager which seems apart from the network script. I added a new network adapter to my virtual machine, and suddenly I have eth1 and eth2 (no longer eth0), neither of which appear to have corresponding ifcfg files. Yet, NetworkManager happily connects/disconnects them and I can get to the internet.
    3. Where can I find more documentation on any of this?
  2. Virtual network adapters. Where can I find more documentation on the details of how they work?
    1. If I have eth0 to be 10.x.x.20, and eth0:0 to be 10.x.x.21, and I sent packets through eth0:0, will the router see packets from the 10.x.x.20, or 10.x.x.21?
    2. How can I expect traffic to route if I set up a virtual adapter?
    3. When my virtual machine's adapter is configured to be NAT, my virtual adapter in the virtual machine can route traffic to the internet just fine. However, when the virtual machine's adapter is bridged to my network, the virtual adapter can't reach the internet at all. Why is this?
For reference, I followed this to setup virtual adapters:
http://collaboradev.com/2011/08/02/crea ... in-centos/

gerald_clark
Posts: 10642
Joined: 2005/08/05 15:19:54
Location: Northern Illinois, USA

Re: Confusion about Virtual Adapters and General Network Set

Post by gerald_clark » 2015/03/05 01:07:55

Do not set 2 adapters on a machine to the same subnet.
Please read the FAQ. http://wiki.centos.org/FAQ/CentOS7

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