From: lws4art@gmail.com
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.
>
> Sorry if this is no help
>
--
Take care,
Jonathan
-------------------
LITTLE WORKS STUDIO
http://www.LittleWorksStudio.com
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
|
