In a recent article, I
discussed why Simple
Mail Transfer Protocol (SMTP) is becoming more and more obsolete, and I
offered my reasons for why the industry should start shopping for a
replacement. In the meantime, however, it’s not enough to just accept SMTP’s
shortcomings. In the article, I suggested that the next-best solution would be
to adopt a SMTP server registration process. Here’s a look at how registered
e-mail servers could not only boost security but also help win the war on spam.
It’s a rare occurrence, but I occasionally receive a note in
my mailbox that someone has sent me registered mail. While registered mail can
be a bit of a hassle, I definitely understand its use.
People send registered mail to guarantee that the right
person—and that person alone—receives the mail. More important, people are
willing to pay more for this guarantee.
Of course, this doesn’t stop someone from sending registered
junk mail, but the key here is cost. Junk mail is less expensive than a regular
piece of mail; that’s why there’s so much of it. If junk mail were more
expensive, it wouldn’t exist.
The same goes for unsolicited commercial e-mail (UCE), more
commonly known as spam. UCE has become such a problem because the cost of
sending millions of e-mails is minimal.
It’s the receiver who bears the brunt of the cost of UCE.
These associated costs include wasted bandwidth, additional storage
requirements, and implementations of filters and other solutions that attempt
to prevent the user from having to manually sort through UCE. And some of these
solutions present their own problems, not the least of which is the loss of
That’s why I believe the industry should consider
implementing a procedure for registering e-mail servers, similar to the process
for registering domains. Until we’ve established globally accepted legal
penalties for sending UCE, spam will continue. So a global Internet body needs
to set the rules.
There are no real standards for filtering UCE and no real
way to ensure the separation of UCE from legitimate e-mail. Everyone does it
differently, and the only real e-mail standard is Simple Mail Transfer Protocol
(SMTP), which really isn’t so simple anymore.
SMTP accepts mail from both e-mail clients and e-mail
servers, making it easy to send junk e-mail. But we can’t throw away SMTP
because the alternative—a complete redesign of the globally accepted e-mail
protocol—isn’t all that feasible.
In my opinion, UCE wouldn’t have become such an issue if
developers had designed SMTP to work more like registered postal mail. And
that’s precisely why I think that the only long-term solution is to require the
registration of all SMTP servers, by IP address, using a system similar to how
root DNS servers operate.
Mail server software might require some modifications for
this system to work, but its basis on existing DNS protocol would make those
tweaks relatively minor. A simple DNS query would be able to determine if a
connecting host were a registered e-mail server. By making the registration
process for SMTP servers similar to the process for registering domain names,
the same legal oversight would apply, accelerating the imminent discovery and
eventual shutdown of rogue SMTP servers.
Right now, we’re playing with solutions that still haven’t
found global acceptance, despite their effectiveness (or perhaps
ineffectiveness) to stop UCE. Presently, companies must implement solutions to
stop UCE either before accepting the e-mail (when it doesn’t know the contents)
or after receiving the e-mail (when it’s too late).
As the war on spam progresses, I fully expect to see more
casualties in the losses of legitimate e-mail and more UCE that infiltrates
inboxes. In my opinion, only when an internationally sanctioned Internet body,
perhaps ICANN, requires SMTP servers to register in the same manner as domain
names will spam cease to be a problem.
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Jonathan Yarden is the
senior UNIX system administrator, network security manager, and senior software
architect for a regional ISP.