Hello, (First of all thanks for the quick answer on the SMTP AUTH LOGIN issue, that's efficiency!) I would like to develop a simple FCL filter for DeleGate but, unfortunately, I have not been able to find any documentation describing how to do it. Peeping through the src I have seen that the fds 0 and 1 should have the handles to the client and server flows, but I could not go any further. Questions: - Is there any description of DeleGate filter development? - Any special consideration for Windows? We have not yet decided to run it on Windows or Linux, and I'm sure that file/sock descriptor passing shows some differences. Regards, Jesus Diego.