Thanks Reco & Greg. I did see the /lib/systemd/network/73-usb-net-by-mac.link file. Thanks for that.
I don't know exactly what is happening, but the MAC address of the device keeps changing after an ifdown/ifup cycle post boot. When the device boots up, it comes up with its own real MAC, but it is failing to get an IP. So, then if I do an ifdown and then a subsequent ifup on it, the MAC then changes to a random number. I also see that the addr_assign_type attribute of the interface changed from 0 (at boot) to 1 (after the ifdown/ifup cycle). It then remains as 1 until I reboot... I also tried adding a udev file (/etc/udev/rules.d/99_fix_usb.rules) with the following content to try to force the addr_assign_type to 0, but this did nothing: SUBSYSTEMS=="usb", SUBSYSTEM=="net", ATTR{addr_assign_type}="0" Also, here is the output showing all that after a fresh boot: user1@server1:~$ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 2: ens4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 00:01:02:03:04:05 brd ff:ff:ff:ff:ff:ff altname enp40s0 3: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff inet 10.8.0.11/24 brd 10.8.0.255 scope global enp1s0 valid_lft forever preferred_lft forever 4: enx001234567890: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:12:34:56:78:90 brd ff:ff:ff:ff:ff:ff inet 8.8.10.10/24 brd 255.255.255.255 scope global dynamic enx001234567890 valid_lft 279980sec preferred_lft 279980sec root@server1:~# cat /sys/class/net/enx001234567890/addr_assign_type 0 root@server1:~# ifdown enx001234567890 Killed old client process Internet Systems Consortium DHCP Client 4.4.1 Copyright 2004-2018 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/enx001234567890/00:12:34:56:78:90 Sending on LPF/enx001234567890/00:12:34:56:78:90 Sending on Socket/fallback DHCPRELEASE of 8.8.10.10 on enx001234567890 to 192.168.64.33 port 67 root@server1:~# cat /sys/class/net/enx001234567890/addr_assign_type 0 root@server1:~# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 2: ens4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 00:01:02:03:04:05 brd ff:ff:ff:ff:ff:ff altname enp40s0 3: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff inet 10.8.0.11/24 brd 10.8.0.255 scope global enp1s0 valid_lft forever preferred_lft forever 4: enx001234567890: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 00:12:34:56:78:90 brd ff:ff:ff:ff:ff:ff root@server1:~# ifup enx001234567890 Internet Systems Consortium DHCP Client 4.4.1 Copyright 2004-2018 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ RTNETLINK answers: Invalid argument Listening on LPF/enx001234567890/96:6e:37:f1:d0:34 Sending on LPF/enx001234567890/96:6e:37:f1:d0:34 Sending on Socket/fallback DHCPDISCOVER on enx001234567890 to 255.255.255.255 port 67 interval 8 send_packet: Network is down dhclient.c:2446: Failed to send 300 byte long packet over enx001234567890 interface. receive_packet failed on enx001234567890: Network is down DHCPDISCOVER on enx001234567890 to 255.255.255.255 port 67 interval 17 send_packet: Network is down dhclient.c:2446: Failed to send 300 byte long packet over enx001234567890 interface. DHCPDISCOVER on enx001234567890 to 255.255.255.255 port 67 interval 14 send_packet: Network is down dhclient.c:2446: Failed to send 300 byte long packet over enx001234567890 interface. DHCPDISCOVER on enx001234567890 to 255.255.255.255 port 67 interval 10 send_packet: Network is down dhclient.c:2446: Failed to send 300 byte long packet over enx001234567890 interface. DHCPDISCOVER on enx001234567890 to 255.255.255.255 port 67 interval 12 send_packet: Network is down dhclient.c:2446: Failed to send 300 byte long packet over enx001234567890 interface. No DHCPOFFERS received. No working leases in persistent database - sleeping. root@server1:~# cat /sys/class/net/enx001234567890/addr_assign_type 1 root@server1:~# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 2: ens4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 00:01:02:03:04:05 brd ff:ff:ff:ff:ff:ff altname enp40s0 3: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:11:22:33:44:55 brd ff:ff:ff:ff:ff:ff inet 10.8.0.11/24 brd 10.8.0.255 scope global enp1s0 valid_lft forever preferred_lft forever 4: enx001234567890: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000 link/ether 96:6e:37:f1:d0:34 brd ff:ff:ff:ff:ff:ff permaddr 00:12:34:56:78:90 On Wed, Feb 16, 2022 at 3:55 AM Flacusbigotis <flacusbigo...@gmail.com> wrote: > My internet connection is off the ethernet port of a PCI-E card that also > has USB ports on it, so the ethernet device is recognized as a "USB > ethernet device"... > > Back in Debian Buster, I learned that the "predictive" naming of this USB > ethernet interface would be governed by "73-usb-net-by-mac.rules" and so I > had it configured accordingly with a config file in > /etc/network/interfaces.d/... Namely that the device name would basically > be its MAC. > > Well, I just upgraded to Bullseye, and I can't bring up the darn > interface. I have tried fiddling around with the device name in my config > file in /etc/network/interfaces.d/ directory, but it just won't come up. > The Networking.service also fails during bootup. > > I also noticed that the 73-usb-net-by-mac.rules file has completely > disappeared, never mind that the official Debian NetworkInterfaceNames page > here <https://wiki.debian.org/NetworkInterfaceNames> still talks about it! > > Anyone know how the heck this is supposed to work in Bullseye? > > BTW, the device shows up as disabled in lshw (I obfuscated the MAC in the > output): > > *-network DISABLED > description: Ethernet interface > physical id: 1 > bus info: usb@7:1 > logical name: enx00XXXXXXXXXX <<<=== Yes, I tried using this > name in the config > serial: 00:XX:XX:XX:XX:XX > size: 10Mbit/s > capacity: 1Gbit/s > capabilities: ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd > 1000bt 1000bt-fd autonegotiation > configuration: autonegotiation=off broadcast=yes > driver=ax88179_178a driverversion=5.10.0-11-amd64 duplex=half link=no > multicast=yes port=MII speed=10Mbit/s > > > >