23rd April 2011, 6:17 PM
One thing I forgot to add.. Gateways can't simply ignore a packet.. It dosn't work that way.. Here's how a DOS works...
A normal connection is made in three packets..
Client --> SYN (Send Request)
Server --> SYN ACK (Send Request Acknowledge)
Client --> ACK (Send Request Acknowledge Acknowledge)
-- Connection is now open..
A DOS attack works like this
Client --> SYN
Server --> SYN ACK
Client --> Does nothing
-- Connection is in limbo consuming router resources
Now to deny a request
Client --> SYN
Server --> KILL Packet
-- Connection is dropped..
Now if you try this...
Client --> SYN
Server --> Does nothing...
Then TCP waits for a time out and request that the conversation be retransmitted.. No help there.. Remember TCP automatically provides for error correction and delivery confirmation.
A normal connection is made in three packets..
Client --> SYN (Send Request)
Server --> SYN ACK (Send Request Acknowledge)
Client --> ACK (Send Request Acknowledge Acknowledge)
-- Connection is now open..
A DOS attack works like this
Client --> SYN
Server --> SYN ACK
Client --> Does nothing
-- Connection is in limbo consuming router resources
Now to deny a request
Client --> SYN
Server --> KILL Packet
-- Connection is dropped..
Now if you try this...
Client --> SYN
Server --> Does nothing...
Then TCP waits for a time out and request that the conversation be retransmitted.. No help there.. Remember TCP automatically provides for error correction and delivery confirmation.