Background Information ======================= Debian 12 Bookworm has been freshly installed on a laptop. The laptop is functioning as a simple home server and has three Ethernet devices, two USB Ethernet adapters and a built-in Ethernet adapter. Ethernet cables are permanently inserted into each of the Ethernet ports on the server laptop, the other ends are only inserted into client devices as needed.
The output of "cat /etc/os-release" is: PRETTY_NAME="Debian GNU/Linux 12 (bookworm)" NAME="Debian GNU/Linux" VERSION_ID="12" VERSION="12 (bookworm)" VERSION_CODENAME=bookworm ID=debian HOME_URL="https://www.debian.org/";; SUPPORT_URL="https://www.debian.org/support";; BUG_REPORT_URL="https://bugs.debian.org/";; IMAGE_ID=live BUILD_ID=20241109T101058Z The output of the "uname -a" command is: Linux debian-12-server 6.1.0-27-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.115-1 (2024-11-01) x86_64 GNU/Linux Problem ========= Since installation, the Ethernet connections have refused to honor the "Connect Automatically" setting in Settings >> Network when a cable from the server is connected to a client. It is my expectation that when a cable from the server is connected to the Ethernet port of a client device, the Debian server will automatically recognize the new physical connection and then automatically activate that connection. Unfortunately, this doesn't happen for any of the server's Ethernet ports. The Debian server will recognize that a new physical connection has been made, which is demonstrated by the change from "Cable unplugged" to "100Mb/s" or "1000Mb/s" in the Network Settings window, but the server will not activate the connection automatically. Each must be manually activated using the toggle either in Network Settings or through the top panel menu for the connection to become usable. This is true for the built-in Ethernet port and the USB adapter ports. Each of the Ethernet devices uses the following common connection profile settings: Details section: Connect Automatically ON Make available to other users OFF Identity section: MAC address - each connection profile is pinned to the MAC address of a different Ethernet adapter IPv4 section: Method MANUAL - the IP addresses are manually assigned so that each adapter uses a different subnet. IPv6 section: Method DISABLE Apart from this problem, all the network connections from the clients to the server function well once they are manually activated. There are no unexpected disconnections or problems with transfer speed. Troubleshooting ================ I have tried deleting and re-creating the Network connection profile for each Ethernet device. I have tried removing and re-inserting the USB ethernet adapters. I have performed all system updates, currently on 12.10. I noted that systemd-networkd service is not running by default. For testing purposes I enabled and started this service, but there was no improvement. I have rebooted the server several times since installing Debian 12 and the problem remains after each reboot. Additional Information ======================= As an example, here is the output of 'ethtool' for USB Ethernet Adapter #1: Supported ports: [ TP MII ] Supported link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Half 1000baseT/Full Supported pause frame use: No Supports auto-negotiation: Yes Supported FEC modes: Not reported Advertised link modes: 10baseT/Half 10baseT/Full 100baseT/Half 100baseT/Full 1000baseT/Full Advertised pause frame use: No Advertised auto-negotiation: Yes Advertised FEC modes: Not reported Speed: 1000Mb/s Duplex: Full Auto-negotiation: on Port: MII PHYAD: 32 Transceiver: internal Supports Wake-on: pumbg Wake-on: g Current message level: 0x00007fff (32767) drv probe link timer ifdown ifup rx_err tx_err tx_queued intr tx_done rx_status pktdata hw wol Link detected: yes Here is the output of 'ip addr' for USB Ethernet Adapter #1 under different circumstances: After physically inserting an Ethernet cable into a client port, but before manually activating the connection on the server: 2: enx3a2a15663da2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 3a:2a:15:66:3d:a2 brd ff:ff:ff:ff:ff:ff After manually activating the connection on the server: 2: enx3a2a15663da2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether c6:37:0d:d1:7b:9f brd ff:ff:ff:ff:ff:ff permaddr 3a:2a:15:66:3d:a2 inet 192.168.1.1/24 brd 192.168.1.255 scope global noprefixroute enx3a2a15663da2 valid_lft forever preferred_lft forever Side Questions =============== Is it normal for 'systemd-networkd' not to be running by default on a fresh installation of Debian 12, as a general rule? I disabled it again after troubleshooting this problem. 'ifconfig' is not installed by default. Is this also normal for a fresh installation of Debian 12?
