A denial-of-service attack that sends an IP packet that (a) has the same address in both the Source Address and Destination Address fields and (b) contains a TCP SYN packet that has the same port number in both the Source Port and Destination Port fields.
A denial-of-service attack that sends an IP packet that (a) has the same address in both the Source Address and Destination Address fields and (b) contains a TCP SYN packet that has the same port number in both the Source Port and Destination Port fields.
Derivation: This single-packet attack was named for "land", the program originally published by the cracker who invented this exploit. Perhaps that name was chosen because the inventor thought of multi-packet (i.e., flooding) attacks as arriving by sea.