No vídeo diz que o host '192.168.1.1__' vai de 100 a 155(apesar de estar escrito 255). Mas, pela doc, eu acho que ele vai de 192.168.1.100 a 192.168.1.199. É isso mesmo?
"The % and _ wildcard characters are permitted in host name or IP address values. These have the same meaning as for pattern-matching operations performed with the LIKE operator. For example, a host value of '%' matches any host name, whereas a value of '%.mysql.com' matches any host in the mysql.com domain. '198.51.100.%' matches any host in the 198.51.100 class C network. "
Fonte: https://dev.mysql.com/doc/refman/8.0/en/account-names.html