From: BitTwister@mouse-potato.com
On Thu, 29 Jun 2023 23:26:57 -0400, Jonathan N. Little wrote:
> Henry Crun wrote:
>> On 29/06/2023 17:43, Jonathan N. Little wrote:
>>> Looking for possible causes. The issue is I have one system where the
>>> MAC address has changed for no apparent reason.
>>>
>>> The system is a MSI B75MA-G43 motherboard with on board
>>> RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller with Ubuntu
>>> 22.04.2 LTS desktop. NIC set to DHCP, and I have a Ubuntu server with
>>> local DNS and DHCP server with a LAN pool where I set this client's IP
>>> by matching the MAC address. Straight forward and easy. Been working for
>>> years. For the third time this year the MAC address has changed where
>>> client has the wrong IP breaking my LAN backup system. My OCD nature I
>>> comment changes to record things so server's dhcpd.conf:
>>> ...
>>> # 2023-03-04 Not sure how but Kenny's mac address changed
>>> # 2023-06-23 Dang Kenny's mac changes again
>>> # 2023-06-29 Kenny is back to previous MAC
>>> ...
>>> host kenny {
>>> #hardware ethernet 1e:2b:ad:33:12:64;
>>> hardware ethernet d4:3d:7e:b6:ba:a8;
>>> fixed-address 192.168.57.132;
>>> }
>>>
>>> Those are the two MAC addresses that NIC keeps switching so this morning
>>> if failed recorded by dhcp server lease file /var/lib/dhcp/dhcpd.leases:
>>>
>>> lease 192.168.57.193 {
>>> starts 4 2023/06/29 09:34:30;
>>> ends 4 2023/06/29 21:34:30;
>>> cltt 4 2023/06/29 09:34:30;
>>> binding state active;
>>> next binding state free;
>>> rewind binding state free;
>>> hardware ethernet 1e:2b:ad:33:12:64; <-NOTE MAC now back to this...
>>> uid "\001\036+\2553\022d";
>>> client-hostname "kenny";
>>> }
>>>
>>> Confirmed on client Kenny:
>>> 2: enp3s0: mtu 1500 qdisc fq_codel
>>> state UP group default qlen 1000
>>> link/ether 1e:2b:ad:33:12:64 brd ff:ff:ff:ff:ff:ff
>>> inet 192.168.57.193/24 brd 192.168.57.255 scope global dynamic
>>> noprefixroute enp3s0
>>> valid_lft 28111sec preferred_lft 28111sec
>>> inet6 fe80::1feb:64a7:bae6:90da/64 scope link noprefixroute
>>>
>>> Now last Friday when I debugged this ip addr command confirmed at the
>>> time the MAC address was d4:3d:7e:b6:ba:a8 and not 1e:2b:ad:33:12:64.
>>> Now it is 1e:2b:ad:33:12:64. HOW? I am not spoofing the MAC with
>>> NetworkManger on Kenny(*). This is an Ethernet and not WiFi with
>>> software MAC switching "pseudo-security" measure some employ on Wifi. I
>>> have not recently updated BIOS on this system, so where should I look
>>> for cause? Puzzled.
>>>
>>> (*)Hostname South Park reference: original machine before rebuild from
>>> scratch with new parts was cobbled together from used systems expecting
>>> a "Hey they killed Kenny" moment at any time.
>>>
>>
>> Looking up d4:3d:7e:b6:ba:a8 I see vendor is Micro-Star Int'L Co.
>
> Which makes sense because it is an MSI motherboard. IIRC that was the
> MAC address that I originally had the dhcp server trap to set the IP.
>
>>
>> Looking up 1e:2b:ad:33:12:64 (three separate web sites) I get "No such
>> vendor, Locally administered addresses (LAA): the address is assigned
>> to a device by a network administrator"
>
> Which is strange because last night it switched to this MAC:
>
> jonathan@kenny:~$ ip link show enp3s0
> 2: enp3s0: mtu 1500 qdisc fq_codel
> state UP mode DEFAULT group default qlen 1000
> link/ether 1e:2b:ad:33:12:64 brd ff:ff:ff:ff:ff:ff permaddr
> c6:51:bd:c3:b2:ab
>
> So the MAC is currently 1e:2b:ad:33:12:64. Now the above has a
> "permaddr" value of c6:51:bd:c3:b2:ab. Googling seems to indicate
> "permaddr" is present when overriding NIC's MAC by spoofing. 1) I am not
> spoofing. 2) c6:51:bd:c3:b2:ab also has no vendor ID.
>
> So I when looking to see where|what could be overriding the MAC like so
> legacy config since this system has been migrated over the years from
> earlier versions of Ubuntu.
>
> 1) No overrides in /etc/systemd/networkd.conf
>
> 2) No overrides in legacy /etc/network/interfaces or
> /etc/network/interfaces.d
>
> 3) Network settings using new netplan as configured by 22.04 installer
> /etc/netplan/01-network-manager-all.yaml
>
> # Let NetworkManager manage all devices on this system
> network:
> version: 2
> renderer: NetworkManager
>
> So using NetworkManager so I checked for any overrides in
> NetworkManager's configuration
>
> 4) /etc/NetworkManager/NetworkManager.conf
> [main]
> plugins=ifupdown,keyfile
>
> [ifupdown]
> managed=false
>
> [device]
> wifi.scan-rand-mac-address=no
>
> Well the Wifi card is not set for random MAC address! But nothing about
> the Ethernet...
>
> 5) Nothing set here either:
>
> jonathan@kenny:~$ ls -l /usr/lib/NetworkManager/conf.d/
> total 16
> -rw-r--r-- 1 root root 225 Jun 9 2022 10-dns-resolved.conf
> -rw-r--r-- 1 root root 80 Jun 9 2022 10-globally-managed-devices.conf
> -rw-r--r-- 1 root root 58 Jun 9 2022 20-connectivity-ubuntu.conf
> -rw-r--r-- 1 root root 306 Apr 4 2022 no-mac-addr-change.conf
>
> So I am at a loss. It looks like the MAC address should be
> d4:3d:7e:b6:ba:a8 which it was the other day but now it is being
> overrided somewhere but I cannot find it.
I would try booting a live cd and checking just to have a second
opinion about mac.
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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