On Wed, Sep 06, 2017 at 12:09:52AM +0200, Giovanni Santini via arch-general wrote: > On that device I am using *systemd-networkd + systemd-resolved* for the > network setup. However, I saw no real method to check if the DHCP > configuration is valid (while NetworkManager provides an element through > DBus inspection). > Does anyone has some knowledge about it? What does it mean a valid DHCP setup? By reconnection you mean that your client re-request a lease from the server? Also, dbus has nothing to do with dhcp settings... In any case, my advice is to get rid of NetworkManager as well as systemd-* tools. If you want a robust dhcp setup on a simple client with a single network card, use dhcpcd (no need even for netctl) because it provides link status detection. But don't use dhcpcd@.service provided with the package, instead replace it with: ->-------- $ cat /etc/systemd/system/dhcpcd\@.service [Unit] Description=dhcpcd on %I Wants=network.target Before=network.target BindsTo=sys-subsystem-net-devices-%i.device After=sys-subsystem-net-devices-%i.device [Service] Type=simple ExecStart=/usr/bin/dhcpcd -4qB -t 0 %I [Install] WantedBy=multi-user.target -<-------- The crucial part is "-Bt 0" which makes dhcpcd wait forever for a lease (read the manpage for other options you might need, for example, in my setup I constrain the demon to only deal with ipv4). My (compatible with read-only root filesystem) /etc/dhcpcd.conf is: ->-------- hostname clientid persistent option rapid_commit option domain_name_servers, domain_name, domain_search, host_name option classless_static_routes option ntp_servers option interface_mtu require dhcp_server_identifier slaac private noipv4ll nohook wpa_supplicant nohook resolv.conf -<-------- these are mostly default settings. Maybe you need to add "nomtu" in case your ISP does something idiotic with this setting (mine does :)). Oh, and hardcode the DNS settings in /etc/resolv.conf, so a broken dhcp server has no control over them. HTH, -- Leonid Isaev