IPSec is a protocol that provides secure communication between two networks or hosts over an untrusted network, such as the Internet. IPSec uses encryption and authentication to protect the data from eavesdropping, tampering, and replay attacks. IPSec also supports pre-shared key (PSK) as one of the methods for initial authentication between the peers

A CNAME record is a type of DNS record that maps a hostname to another hostname. This is useful when you want to use a different hostname for a server than its actual IP address.
In this case, the technician is setting up DNS records on local servers for the company's cloud DNS to enable access by hostname. This means that the users will be able to access the servers by their hostnames, instead of their IP addresses.
To do this, the technician needs to create a CNAME record for each server. The CNAME record will point the hostname to the server's IP address.

A broadcast storm is most likely occurring when connecting multiple unmanaged Layer 2 switches with multiple connections between each pair. A broadcast storm is a situation where broadcast packets flood a network segment and consume all the available bandwidth. It can be caused by loops in the network topology, where broadcast packets are endlessly forwarded by switches without any loop prevention mechanism. Unmanaged switches do not support features such as Spanning Tree Protocol (STP) or Rapid Spanning Tree Protocol (RSTP) that can detect and block loops. Reference: https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/10556-16.html