tcp application exit will send FIN always?

Question

Hi,

When a TCP application exits it will send a FIN packet.

Consider a tcp client which get connected to a always listening server(server never exits).

if the tcp client is exiting abruptly after few exchange of packets, will it always send a FIN packet to the server?

Thx!

Answer 1

Under normal operation , a FIN will be sent ,yes.

Here's a few cases where a FIN is not going to be sent.

• Someone yanks out the network cable of the client.
• The client gets nuked
• The FIN packets are dropped on the way.
• The OS on the kernel crashes hard.