Re: [lwip-users] raw API

[Sergio R. Caprile]

My first advice: please do not post capture snapshots, post capture 
files. And please post the whole session...
My second advice: please describe what you are trying to do and how do 
you think you are not achieving that.

192.168.0.1 is ... ? looks like the client, since it is issuing a RETR
192.168.0.2 is ... ? so the server...
The server answers the RETR
Do those TCP ACKs belong to this conversation ? As those are not 
standard ports, I tend to think they are not. If I had the capture, I 
could check and figure out by myself, among other things...
In FTP, you either let the server connect to you at port 20 or you use 
passive mode and let the server inform you where he is going to be 
listening and you connect there.
If you will not use passive mode and want to use a different port 
number, you usually instruct the server BEFORE actually asking it for data.
The usual sequence is:
USER
PASS
PORT
RETR
The server seemed to have sent some data to somebody at port 49157 
(0xC005 -> 192,5), but since I don't have prior info, I can't tell.
You seem to try to instruct the server to call you at 202,82 -> 0xCA52 = 
51794; is that what you want ? Then do it before RETR and have 'someone' 
actually listening there.
BTW, if you want/need an FTP client, there is one I contributed to (and 
tested) in github: https://github.com/gezedo/lwftp

BTW, can you also post a link to that RAW API FTP server ? I'd like to 
try it.