Troubleshooting Course Content Rough Drafts-How Does Email Work
What is e-mail?
Often referred to as "e-mail", this term is frequently used or associated with the discussion of not only actual "mail" composition and retrieval, but is also used in the explanation of different protocols, standards, and architecture(s) associated with the electronic creation, submission, and retrieval of electronic messages.
We can see how "e-mail" is defined below;
messages distributed by electronic means from one computer user to one or more recipients via a network.
send an e-mail to (someone).
In this training unit, we'll look at how e-mail came about, the industry standards and protocols used today as well as the architecture and vernacular of how e-mail works within your Zimbra deployment.
The origin of e-mail and industry standard protocols
History and Background:
Dating back to the early 1960's, the first form(s) of e-mail sprouted up in the form of services like AUTODIN, a legacy data communications service developed by the U.S. Department of Defense, and MIT's CTSS Mail, where remote terminals could dial-in to share and store files on a central disk(s). Informal methods of using these type(s) of systems later evolved to pass messages between terminal users.
The first "e-mail" systems used different features and ran on different systems that were not compatible with each other; coined "host-based e-mail systems". Most of these systems required users to be logged into in the same "terminal" or "mainframe" in order for communication to occur.
Subsequent to "host-based e-mail systems" cam "LAN e-mail systems", those that ran on a local area network, which still required users to be logged into the same infrastructure. Some examples of "LAN e-mail systems" include Microsoft Mail and Lotus Notes. Further evolution allowed for these types of systems to communicate outside of an organization, assuming the same email system and proprietary protocols were in use.
Circa the 1970's, more of what we see in use today was in the origin of development. It was essential that as organizations grew larger and as technology advanced, those methods of mail exchange between remote sites or other organizations provided an avenue to transport messages of text globally via telecommunication links.
Internet Message Format:
Alas, through RFC, an "Internet Message Format" was derived and published by Qualcomm. RFC5322 is not the first RFC to establish an "IMF", albeit it's the most current.
This document specifies the Internet Message Format (IMF), a syntax for text messages that are sent between computer users, within the framework of "electronic mail" messages. This specification is a revision of Request For Comments (RFC) 2822, which itself superseded Request For Comments (RFC) 822, "Standard for the Format of ARPA Internet Text Messages", updating it to reflect current practice and incorporating incremental changes that were specified in other RFCs.
You can read more about this RFC here; RFC5322.
Beyond Text...Multimedia Attachments (MIME):
Further expansion led to "e-mail" that not only included text, but multimedia attachments as well. Established in RFC2045, through RFC2049, Multipurpose Internet Mail Extensions or "MIME" were derived.
Consisting of two major components, e-mail messages include both a "header" and a "body" section.
This section is structured into fields, such as From, To, CC, Date, Subject, and other information pertaining to the message. An example "header" section is shown below:
Received: from zimbra.server.com (LHLO zmail.zimbra.com) (10.137.27.36) by zimbra.server.com with LMTP; Sat, 31 Jan 2015 01:05:53 -0800 (PST) Received: from localhost (localhost [IPv6:::1]) by zmail.zimbra.com (Postfix) with ESMTP id 7970049F7 for <email@example.com>; Sat, 31 Jan 2015 01:05:53 -0800 (PST) X-Spam-Flag: NO X-Spam-Score: -0.3 X-Spam-Level: X-Spam-Status: No, score=-0.3 tagged_above=-10 required=6.6 tests=[ALL_TRUSTED=-1, BAYES_50=0.8, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1] autolearn=ham Authentication-Results: zimbra.server.com (amavisd-new); dkim=pass (1024-bit key) header.d=zimbra.server.com Received: from zmail.zimbra.com ([IPv6:::1]) by localhost (zimbra.server.com [IPv6:::1]) (amavisd-new, port 10032) with ESMTP id rPQ4Stk2X1Sy for <firstname.lastname@example.org>; Sat, 31 Jan 2015 01:05:52 -0800 (PST) Received: from localhost (localhost [IPv6:::1]) by zmail.zimbra.com (Postfix) with ESMTP id 3E2384A4C for <email@example.com>; Sat, 31 Jan 2015 01:05:52 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.8.4 zmail.zimbra.com 3E2384A4C DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zimbra.server.com; s=C3C5BF8A-F777-11E3-8DD3-AC39CE8301E4; t=1422695152; bh=Md/ZQuH3wBFYNgW54KVDFg+v7hPPpgL/IhUsRmloLgo=; h=Date:From:To:Message-ID:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding; b=CtwrbkKwMSHHXEV53Ksr/I3A+Q+xI8P4ODButvf8yGPWP+5rqIi0ImWCYljTgKAVN IF+xJYUnMhi02RvU6u1g33Ee2UkG/8nIkcTMugqLAAFAZabRQmntI6RzFgyCzcp8sB tcC/xz+Z3CPLjujeHag1GRrX2owsKWubaWPJDGic= X-Quarantine-ID: <24DhbFXYNwUn> X-Amavis-Modified: Mail body modified (using disclaimer) - zimbra.server.com X-Virus-Scanned: amavisd-new at zimbra.server.com Received: from zmail.zimbra.com ([IPv6:::1]) by localhost (zimbra.server.com [IPv6:::1]) (amavisd-new, port 10026) with ESMTP id 24DhbFXYNwUn for <firstname.lastname@example.org>; Sat, 31 Jan 2015 01:05:51 -0800 (PST) Received: from zimbra.server.com (localhost [127.0.0.1]) by zmail.zimbra.com (Postfix) with ESMTP id E388C4A46 for <email@example.com>; Sat, 31 Jan 2015 01:05:51 -0800 (PST) Date: Sat, 31 Jan 2015 01:05:51 -0800 (PST) From: admin <firstname.lastname@example.org> To: email@example.com Message-ID: <1205797309.15.1422695151122.JavaMail.firstname.lastname@example.org> In-Reply-To: <843455228.13.1422695143436.JavaMail.email@example.com> Subject: Re: ZCS Backup Report: SUCCESS MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Auto-Submitted: auto-replied (zimbra; vacation) Precedence: bulk X-Mailer: Zimbra 8.0.6_GA_5922 Thread-Topic: ZCS Backup Report: SUCCESS Thread-Index: FP1J+yf4TQ4duzXiVDb92nMu0M2BmQ==
Included in the body is basic content in form of unstructured text; possible containing a signature block at the end. The content of this section would be comparable to the "body" of a regular letter.
An example "body" section can be seen below:
Hello, During the Zimbra Admin Training class, we will be installing Zimbra on Amazon EC2 instances. Sincerely, Your Zimbra Training Administrator Zimbra | Community & Collaboration 1855 S Grant Street, Suite 200, San Mateo, CA 94402 USA
Simple Mail Transport Protocol