CentOS - Jul 2017 - C7 and spoofed MAC address

Got a problem: a user's workstation froze. He wound up rebooting, without
calling me in first, so I dunno. But, and this is a show-stopper, when it
came up, it came up with the firmware MAC, not the spoofed one. In
/etc/sysconfig/network-scripts/ifcg-eth0, I've got the spoofed MAC
address, and a UUID. In the grub.conf, I've got net.ifnames=0
biosdevname=0. But when I logged onto his machine, ip a showed eth0... but
with the firmware MAC.

And I'm wondering if it went to renew its IP address, and lost the spoofed
MAC. That might explain his freezes.

Anyway, does anyone have any idea if there's some networkmangler or
systemd configuration that would force it to pay attention?

Note that my hack to fix it was ifdown eth0/ifup eth0, and it's fine.

      mark

On 30 June 2017 at 18:58,  <m.roth at 5-cent.us>
wrote:
> Got a problem: a user's workstation froze. He wound up rebooting,
without
> calling me in first, so I dunno. But, and this is a show-stopper, when it
> came up, it came up with the firmware MAC, not the spoofed one. In
> /etc/sysconfig/network-scripts/ifcg-eth0, I've got the spoofed MAC
> address, and a UUID. In the grub.conf, I've got net.ifnames=0
> biosdevname=0. But when I logged onto his machine, ip a showed eth0... but
> with the firmware MAC.
>
> And I'm wondering if it went to renew its IP address, and lost the
spoofed
> MAC. That might explain his freezes.
>
> Anyway, does anyone have any idea if there's some networkmangler or
> systemd configuration that would force it to pay attention?
>
> Note that my hack to fix it was ifdown eth0/ifup eth0, and it's fine.
>

Not much to go on here ....

Your ifcfg-* configs would be helpful.

There was a slight change to MAC spoof behaviour in the NM 1.4.0 that
was part of EL7.3 compared to the older NM as I recall

https://www.hogarthuk.com/?q=node/18

That may or may not be affecting you.

On 07/07/2017 02:13 AM, James Hogarth wrote:
> On 30 June 2017 at 18:58,  <m.roth at 5-cent.us> wrote:
>> Got a problem: a user's workstation froze. He wound up rebooting,
without
>> calling me in first, so I dunno. But, and this is a show-stopper, when
it
>> came up, it came up with the firmware MAC, not the spoofed one. In
>> /etc/sysconfig/network-scripts/ifcg-eth0, I've got the spoofed MAC
>> address, and a UUID. In the grub.conf, I've got net.ifnames=0
>> biosdevname=0. But when I logged onto his machine, ip a showed eth0...
but
>> with the firmware MAC.
>>
>> And I'm wondering if it went to renew its IP address, and lost the
spoofed
>> MAC. That might explain his freezes.
>>
>> Anyway, does anyone have any idea if there's some networkmangler or
>> systemd configuration that would force it to pay attention?
>>
>> Note that my hack to fix it was ifdown eth0/ifup eth0, and it's
fine.
>>
>
> Not much to go on here ....
>
> Your ifcfg-* configs would be helpful.
>
> There was a slight change to MAC spoof behaviour in the NM 1.4.0 that
> was part of EL7.3 compared to the older NM as I recall
>
> https://www.hogarthuk.com/?q=node/18
>
> That may or may not be affecting you.
I am using Centos7-armv7hl and have had no problem altering my MAC 
address.  Much easier than back in Centos6.  All I have needed is in 
ifcfg-eth0 like:

DEVICE="eth0"
BOOTPROTO=none
ONBOOT="yes"
TYPE="Ethernet"
NAME="eth0"
MACADDR=02:67:15:00:E0:02
MTU=1500
DNS1=192.168.224.2
GATEWAY="192.168.224.1"
IPADDR="192.168.224.2"
NETMASK="255.255.255.0"
IPV6INIT="yes"

No grub.conf but

cat /boot/extlinux/extlinux.conf
#Created by RootFS Build Factory
ui menu.c32
menu autoboot centos
menu title centos Options
#menu hidden
timeout 60
totaltimeout 600
label centos
     kernel /vmlinuz-4.9.30-203.el7.armv7hl
     append enforcing=1 root=UUID=ad25a528-baf4-469c-bd12-5276e8f5f9ae
     fdtdir /dtb-4.9.30-203.el7.armv7hl
     initrd /initramfs-4.9.30-203.el7.armv7hl.img

Oh, ip addr shows:

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast 
state UP qlen 1000
     link/ether 02:67:15:00:e0:02 brd ff:ff:ff:ff:ff:ff
     inet 192.168.224.2/24 brd 192.168.224.255 scope global eth0
        valid_lft forever preferred_lft forever
     inet6 2601:4:2001:7302:67:15ff:fe00:e002/64 scope global 
noprefixroute dynamic
        valid_lft 2147448sec preferred_lft 604765sec
     inet6 fe80::67:15ff:fe00:e002/64 scope link
        valid_lft forever preferred_lft forever

BTW, the reason I change my MAC is to thus hand-craft my IPv6 address.  
6715 is my IANA Enterprise number and e002 is the IPv4 subnet address.  :)