Greylisting -- Was: Anti Spam

Eric Crist mnslinky at
Sun Apr 29 13:00:42 UTC 2007

On Apr 29, 2007, at 4:00 AMApr 29, 2007, Ted Mittelstaedt wrote:
> If the monitoring system notices something down, I have to know about
> it within a few minutes.  I cannot wait for the mailserver that  
> sends the
> page out to retry sending the page to the cell carrier's mailserver
> in an hour.
> Things go down rarely.  The moonitoring system is not continually  
> sending
> out pages to my cell phone every day.  Many times many months will  
> pass
> in between the monitoring system sending my cell phone a page.  If the
> cell phone company was running greylisting, any whitelist entry for my
> monitoring system would be gone by then.
>> Even if it does take an hour, the fact that it retried the server on
>> the other side doing the greylisting means it would be whitelisted
>> after a couple mails.
> But the whitelist would have expired by the next time there was a  
> problem.
>> If you're doing something SO critical that
>> three or four mails delayed an hour, until you're establishes as a
>> legit user, means life or death, you definitely should be doing
>> something that backs up how you communicate with other sites,
> I'm monitoring systems at the ISP I work at.  No, it is not life or  
> death
> if a feed goes down for 3 hours and a bunch of people cannot download
> their daily freebsd-questions mailing list fix.  At least, I don't  
> think
> so.  But they do.  And as their money that buys the ISP's product puts
> the bread on my table, I have to do what they want.  And they want  
> instant
> response if there is a problem in the ISP's systems.  That won't  
> happen if
> the monitoring system's e-mails that get sent out when there is a  
> problem
> lie around in a mail queue for an hour waiting for a greylist at the
> cell company to let the messages through.

My ISP has a FreeBSD with a GSM modem with text messaging service.   
They send actual text messages across the cellular network -  
instantly.  No email required.  Perhaps you folks could do that?

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