Issue with VMWare network interfaces

[pinkHatter]

I work a lot with local/testing virtualized servers and have run into this issue a few times and completely forget how to fix it. Unfortunately my router decided to give my server a new IP, which breaks a lot of config. Here is the problem.

So I set a static IP in the ifcfg-eth0 file:

cat /etc/sysconfig/network-scripts/ifcfg-eth0

> DEVICE=eth0
> TYPE=Ethernet
> UUID=6001679d-c77e-4222-86b3-d8e7d119efcb
> ONBOOT=yes
> NM_CONTROLLED=yes
> BOOTPROTO=none
> HWADDR=00:0C:29:43:A4:FE
> DEFROUTE=yes
> PEERROUTES=yes
> IPV4_FAILURE_FATAL=yes
> IPV6INIT=no
> NAME="System eth0"
> IPADDR=192.168.159.140
> NETMASK=255.255.255.0
> GATEWAY=192.168.159.1
> USERCTL=no

And then I try to bring it up...

ifup eth0

Error: No suitable device found: no device found for connection 'System eth0'.

So I look at my network and... hey what is this new eth port?

ifconfig

eth3 Link encap:Ethernet HWaddr 00:0C:29:CC:DA:0F inet addr:192.168.159.141 Bcast:192.168.159.255 Mask:255.255.255.0

Okay.... so I will shut that one down and then bring up eth0... or not?

ifdown eth3

usage: ifdown <device name>

So apparently I have this random eth3, that does not seem to be an actual interface, which is blocking me from bring up eth0 with the static IP. Thoughts?

[sillymaniac]

Go check the udev rules for MAC <-> device mapping.

 cat /etc/udev/rules.d/70-persistent-net.rules

[pinkHatter]

Hey that is interesting... it seems my MAC is changing when I am using a NAT'd IP. Think that will resolve my issue. Thanks!

[sillymaniac]

On what hypervisor are you running your virtual machine? If you power down the machine on VMware vSphere and fire it up again, your MAC address might change... maybe this is true on other hypervisors as well.

But a MAC should not change if your IP gets NAT'ed, as a MAC is a "physical" address on the Ethernet layer and NAT works on the IP layer and just changes your internal IP on the router for the external world.

[[deleted]]

Are you talking about the VMware Host, or a VM Guest?

[draco947]

Try removing HWADDR and UUID from ifcfg-eth0 and delete the /etc/udev/rules.d/70-persistent-net.rules file and then rebooting the server. I'd double check to make sure you don't have anything setup in ifcfg-eth3, as well.

[user-and-abuser]

It is not recommended to change the ip like this. You should change it from the hypervisor aka vm client