On Tue, Sep 26, 2023, 15:32 Mark Rogers <mark@xxxxxxxxxxxxxxxxxxxx> wrote:
On Tue, 26 Sept 2023 at 13:08, Mantas Mikulėnas <grawity@xxxxxxxxx> wrote:Depends on what exactly runs dhcpcd and wpa_supplicant. Is that done by networking.service (ifupdown)? NetworkManager? Are they standalone services?How do I tell?
Run `systemctl status <pid>` or browse `systemd-cgls` to map a process to its .service unit.
(System is a Pi running an elderly Raspbian. The issue I am having is that the device is not getting an IP address - if i wait until booted I have to issue "ip link set eth0 down" and "ip link set eth0 up" to get it to retry the DHCP request
("up" alone isn't sufficient, despite "ip addr" showing the interface as DOWN.
I think you're confusing two different states, which have similar indications – "administrative" up/down that you control (the "<UP>" flag, with nothing shown when down) and "operational" up/down that represents the actual interface status (the "<RUNNING>" vs "<NO_CARRIER>" flags and/or the "state XXX" field).
"state DOWN" is *not* directly controlled by `ip link set up` – it's the result of the interface being operative for any other reason even though it is administratively <UP> (i.e. turned on).
I'm still not entirely sure of the situation but right now it sounds like the configuration is okay but the Ethernet interface is failing to establish a physical link on the first try. Does it also show "<UP,NO_CARRIER>" within the interface flags?
I am assuming that this is because the config file isn't in place when dhcpcd starts but I may be mistaken.)I would generally expect Before/Wants=network-pre.target to work, but that relies on your network services themselves being set up correctly – they too need to order themselves After that target.In that case I should probably return to Before/Wants=network-pre.target and work out what is breaking it, but same question as above: how do I figure that out?
`systemctl cat` for direct configuration and `systemctl list-dependencies --after` (if I remember it right) should be a good start.
--Mark Rogers
