How is the first datagram in a TCP session identified?

The objective of the question is to make you think about TCP connections. How does TCP establish a connection? Look at the flags that are set in the packet. (TCP part of the frame -- 4thin the list)

Also identify the source and destination IPs and ports. Notice the port number and think about the protocol you are using.

It shows the first Syn. It's the first one because the Syn doesn't have an acknowledgment with it. Therefor it's the first connection made.

This is known as the 3 way handshake

FTP Client ......................................FTP Server

-----------------SYN----------------------->

<-------------SYN----------ACK------------

-------------------ACK------------------------->