Re: exim/postfix comparisons
Nate Duehr wrote:
Ick. Do you monitor port 25 outbound at your border for spikes in
traffic? Seems like in some cases that would be the only way you'd ever
see it when dealing with the low-end ultra-clueless hosted customers.
No idea, I don't work in that department :) There's monitoring for all
sorts of things, but since a lot of clients send out legitimate news
letters (sometimes over 100k), it's not easy to react to spikes in
outgoing traffic.
Ever had your entire netblock dumped into one of the major spam
"fighting" sites...
SORBS? They listed a /16 once. Worse is they want you to pay them to
clear your IP (last time I was involved in that). But my pet hate is
Microsoft who seems to randomly blacklist IP addresses. My server that
handles my own personal mail, and nothing else, that has proper
forward/reverse DNS and SPF, had no problem sending mail to hotmail for
ages, and then, all of a sudden, the mail started disappearing into thin
air -accepted by their servers, just discarded. Didn't even make the
junk folder. Took three weeks to get my IP whitelisted.
The real answer has been, and always will be... a method to authenticate
both servers and end-users of e-mail, end to end. Until that day, spam
reigns supreme, no matter how hard anyone tries.
SPF seems to make a reasonable stab at it. At least mail then has to
have really come from where it claims to.
What made this a pleasure to work with, was that after fixing the
relay issue, I could move all the mail in the active queue to the hold
queue, so mail was instantly flowing as normail, which gave me all the
time in the world to delete the spam and requeue the legitimate mail.
qmail (to the best of my knowledge) doesn't have a way to do this.
Yeah. Managing mail via moving files is far more sane than dealing with
specific mail queue commands, different on every system. Moving files
seems much more "Unix-like" to me.
Actually, no, postfix has the postqueue and postsuper commands.
Deleting or moving around files in it's queue can corrupt it (as far as
I know, I've never tried). Problem with qmail here is moving files
around in the queue will corrupt the queue too, except if you stop qmail
first. that's why you'll see qmHandle stop qmail first, then do
whatevery you tell it to do, then start it again. Another nasty side
effect, is that bounced mail have a bounce file somewhere in the queue
structure. When you delete the mail, but don't delete the bounce file
too, this comes back to haunt you. Next time you get a mail with the
same queue ID (and qmail recycles queue IDs pretty damn quickly), qmail
gets confused between the new mail and the bounce file and fires off
mails to everybody. I don't remember the exact detail of how it works,
but it pretty much always results in an angry customer on the phone.
Nasty...
--kj
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