Closes #2828. Squashed commit of the following: commit 26c6cf81c32469e1c4955aafb40490c29b4d1a99 Author: Ainar Garipov <A.Garipov@AdGuard.COM> Date: Tue Mar 30 17:43:53 2021 +0300 dhcpd: do not assume mac addrs of 6 bytes