[TCP] My OS acked the packet but windows is still sending

[nifanfa]

I see that you use same source and destination port. I am not TCP expert, but it seems wrong to me. I think you should use different port for you and different port for server.

No that still didn't help

[nifanfa]

One thing should be notice of is that the lag between vmware and windows is very high

[nifanfa]

Help wanted!

[iansjack]

well I am not sure what is this connection supposed to do, but it seems like you are not responding to request in PSH ACK packet, you just ancknowledge it with length 0, so windows is trying to get some answer from you.

So all i have to do is send the same packet to windows with PSH ACK flags?

You have changed the packet so that the source and destination MACs are correct, haven't you?

[nifanfa]

well I am not sure what is this connection supposed to do, but it seems like you are not responding to request in PSH ACK packet, you just ancknowledge it with length 0, so windows is trying to get some answer from you.

So all i have to do is send the same packet to windows with PSH ACK flags?

You have changed the packet so that the source and destination MACs are correct, haven't you?

MACs are all correct

[nifanfa]

The problem is solved. It is caused by that i allocated the network buffer on the stack using "stackalloc byte[]", but I didn't zerofill it. so there are full of garbage data on that address which made TCP go wrong

[nifanfa]

The cause that make windows continuing resending the packet is the incorrect tcp checksum