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I'm running Ubuntu 10.04 LTS and VMvware workstation 7.0.1 build-227600. The virtual machine i'm running in VMware is a custom distribution built on Debian Linux version 3.1. I'm still pretty much a beginner with UNIX administration. After having messed around with the vmware (changed only the name of the folder, the vmx and and other .v* files accordingly in which the .vmx was situated, and the configuration in the vmx file accordingly), the network devices on the virtual machine do not work anymore. The virtual machine is used for securely sending messages.

The virtual machine:

As far as I know, this perl file called proxy-gen-ifalias eth0 is responsible for properly setting up the two virtual network devices eth0 and eth1.

The Virtual machine comes with a GUI interface in which I have set up two ethernet network devices, one internal, the other external. Now, after having messed around with this, the UI gives me this error message:

perl proxy-gen-ifalias eth0
perl proxy-gen-ifalias eth1
ifdown eth0
ifdown: interface eth0 not configured
ifdown eth1
ifdown: interface eth1 not configured
perl proxy-gen-netcfg
ifup eth0
SICCSIFADDR: No such device
eth0: ERROR while getting interface flags: No such device
SIOCSIFNETMASK: No such device
eth0: ERROR while getting interface flags: No such device
Failed to bring up eth0.
ifconfig eth0
eth0: error fetching interface information: Device not found
make: *** [/etc/network/interfaces] Error 1

Here are the contents of the two perl files referred to in the message: proxy-gen-netcfg

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I've found an ad hoc solution for my problem. But I'd really appreciate it if someone could explain why this could/would happen. – Uku Loskit Jul 27 '10 at 14:52
up vote 2 down vote accepted

Try doing

ifconfig eth2 up
ifconfig eth3 up

And so on until you find which one comes up, then change your scripts to use those interfaces. If you removed and readded the virtual nic's the eth number can change.

You can stop it from changing by running the commands

rm /etc/udev/rules.d/70-persistent-net.rules
rm /lib/udev/rules.d/75-persistent-net-generator.rules

Your error may be caused by something else but the DEVICE NOT FOUND errors are pretty typical for me when I mess around with virtual interfaces because of this problem.

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To elaborate on Pratik's answer, which I believe to be the right one, Ubuntu systems associate a discovered NIC with the mac address, so when you copy or clone an Ubuntu VM (or any operation that results in a mac address change)m you get new NICs instead of reusing the old ones. You can see all the NICs that the system has by doing ifconfig -a. To reset Ubuntu so that the system recognizes "the first NIC" as the first NIC and so on, you'll need to remove 70-persistent-net.rules in /etc/udev/rules.d. On my ubuntu VMs, I typically have a script that removes that file if it doesn't detect an eth0, so this happens automatically. I'm sure there are more elegant ways to handle this though.

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From your messages, it looks like the virtual network interface(s) did not make it through your changes. - "eth0: ERROR while getting interface flags: No such device"

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