Search notes:

Linux: networking

nmcli is a command-line tool for controlling the NetworkManager
iwconfig (which is deprecated in favor of iw) is similar to ifconfig, but dedicated to the wireless interfaces.
lo is the Virtual loopback interface
ss is a tool to investigate network ports.

systemd

systemd-networkd

systemd-networkd is a system daemon that manages network configurations: it detects and configures network devices as they appear and might create virtual network devices.
Enabling systemd-networkd.service also enables systemd-networkd-wait-online.service, which is a oneshot system service that waits for the network to be configured.
systemd-networkd-wait-online.service has WantedBy=network-online.target, so it will be started only when network-online.target itself is enabled.
Check if systemd-networkd is activated: 
systemctl is-activated systemd-networkd

systemd-networkd-wait-online.service

By default, systemd-networkd-wait-online.service waits for (all/at least one?) network to be configured.

systemd-resolved

systemd-resolved is the service that provides network name resolution to local applications via
  • a D-Bus interface,
  •  the NSS service, and
  • a local DNS stub listener on 127.0.0.53
systemd-resolved is configured in
  • /etc/systemd/resolved.conf
  • /etc/systemd/resolved.conf.d (drop-in conf files)

netctl

netctl is an Arch Linux related network manager.

Profiles

netctl uses profiles to manage networks.
Profiles can be started automatically or on demand, depending on the mode of operation.
Profiles are stored under /etc/netctl, example profiles under /etc/netctl/examples.
Profiles can be started on the command line with 
netctl start profile-name
In case the profile cannot be started, use one of the following two commands 
journalctl -xn
netctl status profile-name
In order to start the profile automatically at start up, it needs to be enabled, which creates a systemd service (unit?) and enables the unit.

Systemd units

netctl systemd units include
netctl.service
netctl@<interface>.service (?)
netctl-sleep.service When enabled, active network profiles are stored and stopped before the machine is put to sleep and restared when the system is resumed.
netctl-auto@<interface>.service Scans «its» interface and tries to start a profile for the found network.
netctl-ifplugd@<interface>.service Starts ifplugd on «its» interface
netctl-wait-online.service Waits for all enabled netctl profiles to come online (if activated)

wifi-menu

wifi-menu is a tool that interactively connects to a wireless network and/or generate a netctl profile.

See also

The shell commands ip-address, ip-addrlabel, ip-l2tp, ip-link, ip-maddress, ip-monitor, ip-mptcp, ip-mroute, ip-neighbour, ip-netns, ip-ntable, ip-route, ip-rule, ip-tcp_metrics, ip-token, ip-tunnel, ip-vrf and ip-xfr.
/proc/net
start wifi

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/Linux/ne...', 1788335008, '216.73.217.21', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/Linux/networking/index(135): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78