In the wake of this I've done a lot of diagramming of email flow to various decision makers. Once upon a time, when the internet was more trusting, SMTP was a simple protocol and diagramming was very simple. Mail goes from originator, through one or more message transfer agents (or none at all and deliver directly, it was a more trusting time back then) to its final home, where it gets delivered. SMTP was designed in an era when UUCP was still in widespread use.
Umpteen years later and you can't operate a receiving mail server without some kind of anti-spam product. Also, anti-spam has been around as an industry long enough that certain metaphors are now ingrained in the user experience. Almost all products have a way to review the "junk e-mail". Almost all products just silently drop virus-laden mail without a way to 'review' it. Most products contain the ability to whitelist and blacklist things, and some even let that happen at the user level.
What this has done is made the mail-flow diagram bloody complicated. As a lot of companies are realizing the need to have egress filters in addition to the now-standard ingress filters, mail can get mysteriously blocked at nearly every step of the mail handling process. The mail-flow diagram now looks like a flow-chart since actual decisions beyond "how do I get mail to domain.com" are made at many steps of the process.
The flow-charts are bad enough, but they can be explained comprehensibly if given enough time to describe the steps. What takes even more time is when deploying a new anti-spam product and deciding how much end-user control to add (do we allow user-level white lists? Access to the spam-quarantine?), what kinds of workflow changes will happen at the helpdesk (do we allow helpdesk people access to other people's spam-quarantine? Can HD people modify the system whitelist?), or overall architectural concerns (is there a native plugin that allows access to quarantine/whitelist without having to log in to a web-page? If the service is outsourced (postini, forefront) does it provide a SSO solution or is this going to be another UID/PW to manage?).
And I haven't even gotten to any kind of email archiving.
Umpteen years later and you can't operate a receiving mail server without some kind of anti-spam product. Also, anti-spam has been around as an industry long enough that certain metaphors are now ingrained in the user experience. Almost all products have a way to review the "junk e-mail". Almost all products just silently drop virus-laden mail without a way to 'review' it. Most products contain the ability to whitelist and blacklist things, and some even let that happen at the user level.
What this has done is made the mail-flow diagram bloody complicated. As a lot of companies are realizing the need to have egress filters in addition to the now-standard ingress filters, mail can get mysteriously blocked at nearly every step of the mail handling process. The mail-flow diagram now looks like a flow-chart since actual decisions beyond "how do I get mail to domain.com" are made at many steps of the process.
The flow-charts are bad enough, but they can be explained comprehensibly if given enough time to describe the steps. What takes even more time is when deploying a new anti-spam product and deciding how much end-user control to add (do we allow user-level white lists? Access to the spam-quarantine?), what kinds of workflow changes will happen at the helpdesk (do we allow helpdesk people access to other people's spam-quarantine? Can HD people modify the system whitelist?), or overall architectural concerns (is there a native plugin that allows access to quarantine/whitelist without having to log in to a web-page? If the service is outsourced (postini, forefront) does it provide a SSO solution or is this going to be another UID/PW to manage?).
And I haven't even gotten to any kind of email archiving.
You're right. It's all gotten (and getting more) horribly convoluted. Mail can't really explained without DNS, and DNS is horribly convoluted in its own right. And you can't explain DNS without touching on IP addressing, and when IPv6 eventually comes out, well, try explaining THAT in a reasonable amount of time. Nice blog! I can't believe I haven't bumped into it before now. I'm adding it to my Google Reader.