Hi Alex,
Thanks for your reply.
[...]
SPF is not about spam. SPF is about forgeries.
Let the spammer use his own domain, fine. It may even be SPF protected.
Who cares if a message is forged or not: if it is from a spammer domain,
I don't want it.
The problem I see is where to get a constantly updated list of spammer
domains. The present system Reject 554 by IP address I think, so its
just another extension to that if we Reject 554 by domains as well.
I could also see a potential problem where a spammer has a compromised
machine on a Tiscali ADSL connection, he looks up from his list email
domains which can send email from smtp.tiscali.co.uk and inserts
user(_at_)tiscali(_dot_)co(_dot_)uk in the MAIL FROM field. Would that
defeat the
protection SPF provides?
In stead of sending out millions of messages from a random domain, the
spammer needs to know the mail configuration of the hacked host, and
use that. Makes life more complicated for him, no?
I'm pretty sure spammers evolve around every change we put in place. the
spammer problem has a list of mail configurations for popular ISPs..
But the most important thing is: you won't get the bounces. At least,
not if everyone starts using SPF records when they receive mail.
If the hacked account gets millions of bounces, how long do you think
it takes before that user will clean his zombie-PC ? I can tell you
this: much sooner than when that same zombie-PC sends mail in your name.
Will using SPF actually cause bounces? My understanding was that said
Zombie pc connects to an SMTP server, says MAIL FROM: <user(_at_)host> etc,
and then the mail server does Reject 554, because the Zombie PC IP
address is not authorised to send mail from that <user(_at_)host>
A recommendation if anyone could help me:
Could you recommend any ISP which has a configurable Reject 554 policy?
I'd like to be able to list envelope-sender and the displayed From:
addresses which I want to be Rejected with code 554. I get many junk
mails from online shops and such that I once ordered things from. Its
often not possible to get them to stop sending me their newsletters etc
unfortunately.
I'd also like to Reject 554 connections to my MX server from IP
addresses which do not have reverse DNS set up on them, and connections
which say HELO with a different domain name to their Reverse DNS.
Thanks for any help, Kind regards
Jon
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