Recieve and Send packets Question

Hi guys, I'd like to ask about send and recieve packets and interpreting it.

Is it possible for a recieve packet to be a send packet as well? For example:

I sniffed this packet. (This is just an example)

0b 00 21 01 XX XX 01 00 XX XX XX


For example this makes a character jump.

Would I be able to resend this exact packet in order to mimic the same action? Or do i need to change some values?

Note: If you are familiar with the first 8 offset, PM me. Probably you know where I'm getting at.

send packets-action you done then send to server
recieve packets-action from server,recieve to your computer

and yes u can mimic action by sending a same packet,

hmm. alright, i'll go from there.

Have another question, how do you know which packets to modify to elicit your desired effect? (well, in cases where you modify some values OR a certain process.)

bump