How are Your SMTP Timeouts Configured?

Asprin asks: "One of the employees at work had a major headache because a very important email was undeliverable for more than 24 hours. Sure, he got an warning from our server about it, but only after an entire day had passed, and the email was no longer timely. Therefore, I shorted the message handling timeouts to send 'delivery delayed' warnings after 30 minutes and to cancel the message as undeliverable after four hours. Now, I don't expect any of the other mail administrators here to bless these timeouts because they're way too short. HOWEVER, the truth is that my users rely on email to be as reliable as telephone messages, and if it can't be delivered immediately, it is better to reject it outright and alert the user so that other communication channels can be exploited such as fax or Fed-Ex. Is anyone else doing this? Are there any non-obvious ramifications lurking? Pros? Cons? Comments? Should we all reduce these timeouts on our SMTP servers?"

Use the message priority flag

[Zocalo]

I'm not sure when the feature was introduced, but later versions of Sendmail allow you to set different timeouts for different message priorities. The necessary settings for your "sendmail.mc" file are:

• confTO_QUEUERETURN_NORMAL
• confTO_QUEUERETURN_URGENT
• confTO_QUEUERETURN_NONURGENT

and the same again with "WARN" in the place of "RETURN". The best thing is, if you set these in a certain way it *really* causes grief for those pricks that like to set the urgent flag on all their emails because they get innundated with warnings. It's like a LART, only without the lawsuit. ;)

Re:Email receipts anyone?

[jonadab]

> What would be nice is if there was a standard for email "read"
> notices. Is there one? I sort of doubt it, considering the hacks
> I've seen to try and emulate it. Outlook has a proprietary thing
> that I doubt works.

This is a fairly old standard. (Pegasus Mail supported it in 2.0,
which was out WAY before there was an Outlook and, for that matter,
before there was a Netscape.) The problem is that privacy fanatics
lobbied the mail client writers to have this feature disabled by
default, even in the mail clients that did support it, and so it
never became reliable and never caught on. Today, of course,
turning it on by default would be insane, because of spam, but
that was not the reason ten years ago. People were concerned that
the sender might know when they read the message and so might
expect an immediate response, and they wanted to be able to claim
they hadn't seen the message yet, if they didn't have time to
respond or just didn't feel like it.