[Techtalk] RE: Email service that does graylisting/razor/spamfiltering/etc?

[Rob McEwen]

Kelly,

I provide just such a service. It does everything you've asked except not
the challenge/response. Additionally, I'd be reluctant to take on a client
who required "catch-all" accounts, or, as you described *@domain1.com
...because this can place a tremendous burden on a spam filter. For example,
in testing, one of my clients for whom I provide this service would have had
40 times the number of their combined hams/spams in volume of mail if
catch-all is turned on, due to dictionary attacks alone. (In case you missed
that, this would be a 40,000% increase in volume resulting from allowing
dictionary attacks through!)

But here are the upsides:

(1) My filtering is of such high quality that you won't miss not having the
challenge/response. (IMO, challenge/response is for wimpy spam filters!)

(2) Even though I don't allow "catch-all" accounts, (a.) I can turn
"catch-all" on for short periods of time if that would help in "finding"
lost aliases that you'd forgotten (b.) Extra "throw-away" aliases attached
to the same e-mail account are unlimited and do NOT increase my prices.

(3) I've been heavily involved in SURBL (and to a lesser extent, URIBL) for
years and, therefore, I've worked towards a quality of filtering that far
exceeds the major "famous" providers, both in terms of spam caught and legit
mail not caught! While I use SpamAssassin as a part of my filtering, most of
my filtering is custom written and I'm beating SA's "out of the box"
configuration by a wide margin.

E-mail me directly (off-list) if you are interested and for pricing!

Rob McEwen
Rob at PowerViewSystems.com

-----Original Message-----
From: Kelly Jones [mailto:kelly.terry.jones at gmail.com] 
Sent: Monday, April 09, 2007 10:35 PM
To: nmlug at nmlug.org; nmosug-l at mailman.swcp.com;
linuxusersgroup at googlegroups.com; techtalk at linuxchix.org;
users at spamassassin.apache.org
Subject: Email service that does graylisting/razor/spamfiltering/etc?

I have about 20 domains, and any email to any of these domains
(anyaddress at any_of_my_domains.com) forwards to a single mailbox.

I handle email for all these domains myself, but it's becoming a hassle:

 % dictionary attacks mean I often get the same spam repeatedly

 % I'm too scared to change my SMTP config (to setup graylisting for
 example) for fear of breaking something and losing email [not that
 99+% of isn't spam anyway...]

 % My SMTP server sometimes gets flooded w/ connections (probably not
 denial-of-service-- just excess-of-spammers), delaying legit email.

In short, I want to to give up: running a mail server used to be easy,
but it's not anymore.

Is there a reliable, fairly inexpensive service that does graylisting,
razor-checking, sender address verification, RBL-checking, and other
spam filtering? Specifics:

 % I'd like to set the MX records for all 20 domains to their server
 and be done with it.

 % I do NOT want to forward email (to a spamarrest.com address for
 example). Forwarding means I still have to run my own mailserver +
 nullifies RBL checks, graylisting, etc.

 % I'd like the option of having challenge-response ("you sent me an
 email + I don't know you -- go here and prove you're human"), but
 also the option of turning it off.

 % Senders should always be notified (ideally at the SMTP level) if
 their message is rejected (ideally w/ a custom reject message that I
 choose). Messages shouldn't just disappear.

 % I'd like the ability to check my email via POP/IMAP. Size limits
 are OK: I plan to download email regularly.

 % Most of the email for my domains will come to just me, but I'd like
 the option to forward a copy of emails to certain addresses/domains
 to others. Example: email to *@domain1.com comes to just me, but
 email to foofoo at domain1.com (that makes it through the spam filter)
 comes to me and a copy gets forwarded to bob at gmail.com. This feature
 isn't critical: I can probably setup Pine rules/etc to do what I want
 if I have to.

Any recommendations?

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