Hello, I've read some documentation and some threads in the forum and I feel a little stupid because I don't get how PMG is supposed to work (I'm pretty noob regarding mail protocol). I made a little picture to show what I understand this far. So basically, I imagine when gmail or any mail server tries to send me a mail this is done on port 25 (maybe 465 also ?) and I should route this trafic to PMG with my firewall (I didn't try it this far, but it's how I imagine the stuff working). Now when I would like to send a mail from my Thunderbird at home, how can I do that, since I'm supposed to register to my mail server on port 465 to be allowed to send the email ? Since port 465 is send to PMG who doesnt know anything about my mail account and can't provide me authentification I don't see how this should work... Should i maybe only send port 25 to PMG and all the other ports (465, 587) directly to my mail server ? Regarding outgoing mail from an internal server, should I send that to PMG also (who will route it back to the mail server) ? I've read the port 26 should be used for that, but I'm wondering what's the use for this since I'm pretty sure that my internal servers are not sending spam... Again sorry if my question is stupid, but I'm trying to find some noob explanation and I didn't find it so far. Have a pleasant night !