Which of the following description on BCP properties is correct?

The LAND attack is performed by the attacker sending a source address and a destination address to the destination host are the destination host, the same SYN packet on source port and the destination port. When the receiver waits for the final ACK packet from the sender, the connection is always in a semi-connected state, resulting in waste of limited TCP resources at the receiving end.

In the OSPF broadcast network, there are 4 routers RTA, RTB, RTC, and RTD in the same network segment. The DR priorities are 2, 1, 1, and 0 respectively, and the router IDs are 192.168.1.1 and 192.168.2.1, 192.168.3.1 and 1924.1 respectively.
If the OSPF protocol is enabled on the 4 routers at the same time, the BDR selected by OSPF is _____.

Which of the following description is true about BGP aggregation?

IPv6 introduces Solicited-Node address, which of the following description about the address is correct?