Re: [lwip-users] TCP keeps re-transmitting but no ACK packet after SYN, SYN+ACK

[address@hidden]

Sergio R. Caprile wrote:
> If we assume the web server is OK (why ?)

Well, I'll have to take the OP's side here: if it is a webserver 
programmed with the socket API, this should in no way result in IP 
checksum errors. This means if the socket webserver is the one 
triggering this, the assumption that this is a bug in lower layers (lwIP 
or the port/driver) is not a bad one.

However, to get to the cause of the problem, using a known-to-work raw 
API app might indeed be the best.

> then something is broken in your port,

Even if it's not too likely, this could still be a bug in lwIP. It's 
just way more likely to be a bug in your port/driver...

> You are using NO_SYS=0, hope you know what your are doing with tasks and
> calling lwIP from just one of them.

When using the sockets API, tasks should not be a problem unless one 
socket is used from multiple threads at once.

> PS: how come you are developing networking applications and don't know
> how to do a plain telnet to a port ? you open a command shell or
> whatever M$ calls it and write "telnet" followed by the port number,

From Windows 7 on (or was it Vista?), telnet is *not* included with 
standard windows any more :-(

>   or install PuTTY.

Right. That's what I do. With that knownledge however, I think you'd 
have to explain what to do with telnet in this case...


Simon