Fighting spam via greylisting

Bruce Dubbs bruce.dubbs at gmail.com
Sun Apr 8 20:32:54 PDT 2007


Randy McMurchy wrote:
> Randy McMurchy wrote these words on 04/08/07 15:43 CST:
> 
>> All mails appear to lag about 30 minutes. From everyone. I'm going
>> on the time the email is sent by the sender, and the time it hits
>> my mailbox. My polling for mail is not the issue.
> 
> There was no reply to my comments. And emails throughout the day
> have been one-half-hour late in delivery. So, we are now looking at a
> half-hour delay in delivering mail so that the "management issues"
> are lessened. This, I'm afraid, will be the death of the project.
> 
> Is lessening the effort to eliminate spam, worth it? We cannot
> continue with a half-hour delay in delivery of mail. This would
> put us totally in an IRC support basis. Are we ready to do this?

Jeremy and I have been working on the mail problem we caused with the
graylisting.  There may have been multiple problems, but we think we've
got them fixed.  The graylisting is backed out and test messages to at
least two lists were posted and echoed back in about 2 minutes.

The theory about the graylisting was to send a 'try again later' message
to the mail servers when first contacted.  After the mail server is
'validated' by trying again, the server is put in a database and
accepted immediately if the same server tries again.

The problem as we can tell is that many large ISPs use multiple servers
for outgoing MTAs.  This causes a delay for every server.  Additionally,
the retry time is up to the sender and delays of hours is not uncommon
if the first connection is rejected.  This is not acceptable for world
wide mailing lists like the ones at LFS.

We're sorry about the delays today, but we can't improve things if we
don't test them out.

  -- Bruce



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