With the following config (see config file below):if only ethernet cable is connected, it 100% works: I can quickly SSH the computer via eth0's IP,if both ethernet cable and wifi dongle are connected, it 100% works: I can quickly SSH the computer via eth0's IP  or wlan0's IP,if only wifi dongle is connected, I have to wait 1min30sec after boot to be able to SSH the computer! It's like the fact no ethernet cable is there blocks the boot* during 1min30sec. Why does the fact no ethernet cable is present in case #3 block the boot for 1min30sec?This is confirmed by:# systemd-analyze blame  1min 28.442s networking.service         353ms getty-static.service/etc/network/interfacesauto loiface lo inet loopbackauto eth0iface eth0 inet dhcpauto wlan0allow-hotplug wlan0iface wlan0 inet dhcpwpa-ssid <myssid>wpa-psk <mypasswd>
Boot blocked during 1min30sec because /etc/network/interfaces
networking;wifi;systemd;ethernet