Our company have Wingate 6.14 and we can't send forwarded e-mails, and we can't attach files to e-mail, from Yahoo. The problem is only with Yahoo. If we connect one PC to internet directly without Wingate, Yahoo e-mail works very well.
Then, I did other test: I installed a trial versíon of Wingate in other network, other company, in other words: in other site, and happen the same problem, only with Yahoo.
I'll appeciate your help.