Re: [lwip-users] HTTP Auth, LWIP connection management and FIN packets

[Sergio R. Caprile]

The piggybacked SYN in frame 4 is considered part of the stream and so
the sequence number in frame 5 is one more than what you would expect.
The RST flag is also a correct response because you close the connection
before the stack can process the FIN (what it would do after you return
ERR_OK, and will call you again to inform you of the closure)
RFC1192 4.4.2.13
https://tools.ietf.org/html/rfc1122#page-87

I'm not sure if the FIN can be considered part of the stream, but I've
found references to that, and lwIP seems to be doing so.

If this is true, the test I suggested should end with the expected FIN
ACK on the client side.