Download Practical Packet Analysis

The WAP responds to the connection attempt by sending a challenge
statement to the client. This statement is an encrypted string of text that
must be decrypted by the client (with the appropriate WEP key) and then
sent back to the WAP, as shown in Figure 10-13.
Figure 10-13: The wireless client sends the
unencrypted challenge text back to the WAP.
In packet 6 the wireless client sends back the unencrypted challenge
text, and the WAP to replies with a message stating that the authentication
process was successful, as shown in Figure 10-14.
Figure 10-14: The WAP alerts the client that
authentication was successful.
Finally, after a successful authentication, the client can transmit an
association request, receive an acknowledgment, and connect, as shown in
Figure 10-15.
Figure 10-15: The authentication process is followed by a sweet and simple association request and response.
Now that we know what a connection to a WAP should look like, let’s
look at the capture file from Justin’s connection attempt. As we see in packet 3
(shown in Figure 10-16), the WAP sends challenge text to Justin’s computer,
so we know that the two devices can see each other.
Figure 10-16: The WAP sends challenge text to Justin’s computer.
Packet 5 (in Figure 10-17) shows the wireless client sending its response to
the server, which tells us that these devices are attempting to communicate.
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