Answer:
DHCP server
Step-by-step explanation:
The first option that we must check is the DHCP server (The Dynamic Host Configuration Protocol) server because this is the protocol that gives us the IP addresses to connect with the internet if we don't have an IP (Internet Protocol) address, we can never have an internet connection, if the DNS fails we cannot connect with the internet, but regularly the DHCP is the main issue if there are not physical issues.