@ dcvirus, since hashes are message digests that cannot be directly bruteforced, random strings are hashed applying the originally used algorithm, and compared against the captured hash. One of such super power tools is up there- below my previous post.
@ Grace_S, What was so rough about WEP becon cracking?
@ OldMaven, tell us about the range of your enthusiasm. I give myself 9.9 out of 10 --- about expertise ~~~ umm.. somewhere on the 3ish. :P 
@ atit, What's your Server's IP address? ;)
 DoS can be as simple as disconnecting the Network Cable from your NIC; to jointly hitting a single box or a cluster with thousands of Zombies (machines running bots or somehow compromised), hogging up the CPU, overflowing memory buffer, or sending tons of junk packets and clog the Network. It doesn't necessarily have to be a SYN flood. Even without a SYN and SYN/ACK (first two steps of a three-way handshake), an attacker can send a continuous stream of ACK packets to cause Denial of Service. For a standalone server (presumably your case), DoS is trivial, since there's no load balancing or failover. 

~@~