email Message-ID: What is a good algorithm to create this?

[Sheila King]

[cross-posted to:  comp.mail.headers, comp.lang.python

follow-ups set to comp.mail.headers ]

I'm writing a cgi script in Python to take input from a form and send results
via e-mail. (So, what else is new?)

Anyhow, my script has two options for sending e-mail:
(1) For those with access to Sendmail, send the message this way. That is the
easiest, most efficient way.
(2) For those without Sendmail access, it is possible to access a SMTP host
and send it that way. However, in this case, it seems my script should
generate the Message-IDs, as some SMTP servers will fill this in but others
will not.

What is a good way for my script to generate Message-IDs? I know it usually
has something to do with random numbers or strings, but I thought I would get
some advice on how to do this, first, before blindly proceeding. A description
of a general algorithm would be fine. Pointers to online resources describing
such are also very welcome.

--
Sheila King
http://www.thinkspot.net/sheila/
http://www.k12groups.org/