[Amps] O.T. Emails Gone.

[mikea]

On Fri, Oct 08, 2010 at 02:38:37PM +0800, Alek Petkovic wrote:
> Every once in a while, postings to this reflector go into a black 
> hole, never to be seen again. It has happened to me twice in the last 2 weeks.
> 
> I just re sent a reply to Carl's email that I had sent some 6 hours 
> ago. It appeared on the list immediately. The earlier copy is still 
> finding its way in the dark, I guess.
> 
> 73, Alek
> VK6APK

These things do indeed happen In Real Life. 

I run the E-mail filters and the externally-visible E-mail servers for a
large government agency, and field complaints from internal and internal
users. One of the most frequent complaints takes multiple forms:

 "External-User sent this mail N days|weeks ago, and I just got it!"
or
 "Internal-User just got this mail, which was sent N days|weeks ago!"
or 
 "I sent External-User mail N days|weeks ago, and it's not there!"
or
 "Internal-User sent me mail N days|weeks ago, and it's not here!"

In all cases, the complaint ends with "Fix your problem!" 

So far, over 10 years of doing this, every case has been an external
mailsystem choking on a piece of E-mail for some time, and only emitting
it when it was tickled in some special manner by its administrator. This
happens most frequently with M$ Exchange systems.

E-mail (the Simple Mail Transport Protocol, or SMTP) is *NOT*, never has
been, and never has been advertised as, a reliable protocol. Delivery
is *NOT* guaranteed. The people and organizations that send critical or
time-sensitive information via E-mail are gambling that it will get there
in time. Most of the time they win, but the house bit-bucket still catches
a piece of E-mail every now and again.

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin