> Only one thing: under CheckPoint FW with IIS 5.0 i need to open DNS-tcp > to permit to send email. I don't know why this, but without DNS-tcp I > can not to send email.
I am not hundred percent sure, but here is a possible explanation for the behaviour you have talked about: Though DNS usually uses UDP, it occasionally has to use TCP for some sites (like say hotmail). Typically their MX record is too large and sending that via UDP is not viable. UDP will need to fragment it and there is no guarantee that each packet has been received. It is in such cases that TCP has to be used. With Regards, Sumit Dhar http://www.rootshell.be/~dhar
