I have searched on the internet for a solution for my problem and I'm sure for also a lot of other people but I can't find the answer. I have installed Thunderbird on my Windows7 professional laptop and I can receive all my mails but I can't send emails out. On my server I have Ubuntu with postfix installed which works perfect with all other computers in my network with Windows XP together with Thunderbird. Then I have searched and read a lot of same problems, so the issue is Windows7 which won't let Thunderbird go through their OS because when I tried Microsoft Outlook with imap this worked fine. I already have disabled the FW in Win7 and added a new rule for port 25 but without success. Maybe someone here on board has a solution for this? Or am I forced now to use another email program?