Hi I have worked in the capacity of Microsoft Exchange server and AD for sometime, but recently have received additional duties and one of them is reading email headers. For example making a determination of why an email was blocked, tagged etc.. on firewall appliance. Any guidance on where I can receive resources to learn RFC's and how internet email work. I don't see a lot of material but only unix resources like postfix and sendmail. I I have been kind of winging it and using google but would like some more formal information about this stuff.