As I stated, I'm unable to access my headless raspberry through SSH, even if I were able to do it before the first reboot. The raspberry's leds are blinking but it seems like it's not connected to router. It's currently running Raspbian Stretch Lite without graphical support, didn't set static IP.
All leds from RJ45 sockets are on. I know the current IP address that was given by DHCP server. I don't get replies by ping in any case. I tried
arp -a but it does show all the other devices, except the raspberry.