eMail: Intro

Electronic mail, originally eMail but now usually written e-mail or simply email, is as old as multi-user computers, predating the Internet and its current spam-flooded form by decades. Despite its age, eMail still remains as one of the most well known technologies empowered by the global Internet, and for many users it may be the only reason to subscribe to Internet access.

The old normal

First, the earth cooled.

In its oldest form, eMail was a basic means of sending textual messages to other users on the same computer system. Its simple form of a body, subject, sender and one or more recipients would be recognizable to modern users who would find the lack of attachments or access to remote users limiting. This model worked well when many users shared a mainframe and files could easily be shared simply by giving the path to the file. When these large multi-user mainframes started to be connected to each other, a means for transferring mail between systems became important and quickly devised using Unix to Unix Copy, a means of remote coping from one host (mainframe) to another. While it was possible to send a mail from a host in Los Angeles, California to one in London, England; the process for doing so was not as simple as it is today by simply specifying the recipient. During this era, a sender was responsible for providing the complete route for the message, stating each host the message would need to go through until it reaches the destination user via a notation known as a bang path.

Imagine if you and your best friend went to different colleges in neighboring states, and you wanted to exchange letters. If the physical postal service operated like electronic mail used to, you would drop the letter at your local post office with instructions that it should next be delivered to the local sorting center, followed by a regional sorting center, and then sent to the neighboring state's central sorting center, which would then send it to a local distribution center near the university, before it would be delivered to the address at the university. If we were to write out these instructions, the post office would ignore it because it wouldn't be efficient to read such a long description. Instead, the post office looks at only the recipient address (or simply the postal code) and determines the best next hop to get there. RFC 821 (IETF Standard 10) made this process much simpler by creating the simple mail transfer protocol which allowed addressing users by the now-familiar syntax local-part@domain.

Then the dinosaurs came.

In the early 1990s, residential Online Service Providers like CompuServe, Prodigy, and American Online had been offering local mail delivery on their systems, but initially were unable to send mail to users of other systems. Meanwhile, corporate users were becoming accustomed to the ability to reach other people all over the Internet, even outside of the same company. As Internet Service providers appeared offering competitive packages including Internet eMail, even the entrenched Online Service Providers introduced gateways between their internal systems and the larger Internet allowing users to exchange mail with friends, family, and co-workers and even strangers regardless of the user's Internet Service Provider.

One of the side effects of users getting an eMail account as part of standard service, either from work or as part of their home Internet access account, was that there was not a large market for third-party eMail hosting. Another side effect, was that when someone changed companies or Internet access providers, they had to change eMail addresses as well. Free Webmail providers appeared, not just as a means of a “permanent” address that could be used across providers but as a way of checking mail while travelling, since by this point, the main options for checking mail while away from home were Internet caf├ęs or public libraries. Still, these free accounts were usually used as secondary accounts; their standard limit of 1MB of mail was constricting even in 2000, and many Web services refused access to free accounts which they considered untrustworthy.

What's Normal Now

…they died and turned into oil.

Google released their Google Mail (also known in much of the world as GMail) Webmail service in 2004 which acted as a catalyst in the shifting view of free mail accounts. When Google's Webmail service provided users with a 1GB of storage data, a useable amount for most home eMail users many users started using it as a primary account. At the same time, younger users who were on their parent's account found free Webmail accounts as the only viable option, and were able to keep these accounts even after moving on with their lives. The ubiquitousness of free-mail accounts—not only from Google but upgraded offerings from competitors like Yahoo and MicroSoft—led to an increased acceptance of these accounts that was missing previously, many service providers found that blocking them would lead to alienating a large potential user-base.

Many users find free Webmail accounts convenient. Others have become increasingly concerned with the lack of protection afforded by them. The law is rarely been quick to adapt to technology, and what little case-law there is around eMail systems was not devised with modern systems like Webmail or the Internet Mail Access Protocol in mind, where users leave mail on a server to access from multiple locations. Instead, they presuppose a system popular in 1986, where users would access mail (e.g. via the Post Office Protocol) and copy it from a remote machine to a local computer for storage and then delete the copy on the servers. While many users would like to save old eMail—love letters or bank statements for instance—under the Electronic Communications Privacy Act, if these were kept for 180 days in your Google mail account, Google would be required to turn over the messages to the government if it asked nicely, without a warrant. A federal case in 2004 brought in Boston, Massachusetts went even further claiming that the mail provider could have unfettered access to any mail that transited through the mail system.

What you can do

Running your own mail server is both one of the most common things to do with your home network connection—running your own Web server and gaming servers possibly being the only things more common. There are many free options which, if you're running a Linux or BSD distribution, are likely included and have easy-to-use guided configuration dialogs. The most popular these days are postfix and exim, while qmail still has a following (Yahoo! uses it). Most mail modern servers offer similar features, although it may take more effort to get the most from some. In some cases, you can install various spam control methods into the mail server itself; other times (e.g. with qmail) you'll need to deal with spam filtering either before or after the message gets to the server. Does that sound complex? It can be, but you can start with a basic postfix or exim installation and modify it as you need to grow complexity.

What do you get for the hassle? Running your own mail server gives you some advantages:

The first two items we've touched on in the previous section. Let's look more at the next two.


eMail isn't just vulnerable when it's stored—it's vulnerable as it moves across the Internet. Fortunately, there are standard ways to deal with this, and ensure that connections between your server and that of your friend are secure. For this you should ensure that you enable Transport Layer Security, both between client and server as well as for server-to-server connections. For the paranoid, you should also verify server certificates, but this could be very limiting. You're better-off installing Pretty Good Privacy instead (or the compatible GNU Privacy Guard) and convincing your contacts to do the same.

Wild-card domains

General spam management is its own article (or more), but one of the simplest things you can do is use different addresses each time you register with or provide your address to a third party. Many freemail providers support using a suffix—such as youraddress+anything@—following the standard the sendmail server supports, but smart to this, some sites have decided to incorrectly reject addresses with the plus sign; besides, if a spammer steals a list of passwords, it's likely they'll strip these suffixes. An easy-to-do alternative is to create a nonce domain with addresses you use not more than once. You can create this as a wild-card domain in your server (accepting all mail) or by adding addresses as you use them and removing them if one is compromised or you otherwise would like to stop receiving mail to it anymore.


Running your own mail server does not mean giving-up access to snazzy Webmail as well. With free interfaces like Roundcube, Horde's Imp, or Zimbra; you can build a complete calendaring system on top of your home mail system and integrated it with your voicemail (but those are tasks for another day).

What will be Normal

SMTP is still the backbone of eMail despite having been standardized back in 1982: regardless if you're using your corporate eMail or a free Webmail account, any message sent from one address to an address hosted elsewhere will be sent using SMTP. For over a decade, various people and companies have proposed alternatives and suggested that eMail is dead. eMail is resilient, and while various instant message and community-based private message systems have been named as eMail killers, none have outlived it and certainly none have replaced it given its pervasiveness, openness, and low barrier to entry.

There has been a bit of a war between larger mail providers (Google, AOL, and various ISPs like Comcast) with smaller mail providers. Many ISPs will not like you running a mail server on your home connection, so you may run into problems with this, or you may need to request a static IP explicitly (usually for a few dollars more in the US; I hear this is standard in some countries). These difficulties have made running your own mail server a bit more of a nuisance that it used to be, but many tech-aware users still run their own servers without giving it another thought.

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