What is a possible countermeasure for SYN floods?
A) SPI Firewall
B) SYN Cookies
C) Block all flags with the SYN flag set, in or out
D) Disable outgoing SYN traffic

Question

Quizplus · Accepted Answer

The other answers might work but would go too far or not be applicable in all situations. SYN cookies allow the receiving host to dump its SYN queue as it sends out the SYN-ACK. If nothing comes back, no harm done. If an ACK is returned, the original SYN queue can be reconstructed based on the SEQ number the receive host chose in its first response.

What Is a Possible Countermeasure for SYN Floods