Which of the following statements are true about firewalking?

To use firewalking, the attacker needs the IP address of the last known gateway before the firewall and the IP address of a host located behind the firewall.

In this technique, an attacker sends a crafted packet with a TTL value that is set to expire one hop past the firewall.

A malicious attacker can use firewalking to determine the types of ports/protocols that can bypass the firewall.

Firewalking works on the UDP packets.