Liste de diffusion Message #15186
De: Lewis Butler <>
Sujet: Re: Host Channel Limit
Date: Tue, 28 Feb 2006 07:30:17 -0700
A: SIMS Discussions <>
X-Mailer: Apple Mail (2.746.2)
On 27 Feb 2006, at 12:20 , Paul Galati wrote:
It is great to see that SIMS is still working well being what it is.  It
is a shame that it is not being developed any longer, in favor of
Communigate Pro.  How much life do you feel SIMS has left in it?

Um... none?

I don't get a ton a good mail but get plenty of blacklisted attempts.  I
still use the Communigate Client EVERY day to monitor our mail traffic.  I
notice that spammers sometimes try to contact me from the same mail server
multiple times simultaneously.  I had my Host Channel Limit set to 3 so
they wouldn't tie up all the connections.  This seems to work OK.  I tried
an experiment and changed the Host Channel Limit to 1.  Everything seemed
fine but one thing I am noticing.  It appears that some mail servers want
to "call" me to verify that I am "calling" them from the same IP.  If the
Host Channel Limit is set to 1, my sending attempt qualifies as that 1, so
the receiving mail server that is "calling" me back for verification of
legit IP is not being served.  I noticed this because mail to a specific
domain started to pile up.  Once I changed the Limit to 2 or more, the
mail was delivered successfully on the next retry.

Contrary to what Bill C said about this being SPF, this is in fact "sender callback verification", where the mailserver you are sending to "dials back" to the mailserver for the account in the envelope-From and tries to send a dummy email to that account.  If this message fails, the connection is usually dropped as coming from a forged address.  SPF is a DNS based anti-spam measure in which a DNS record is created specifying the domains a mailserver handles, and if any other mail server handles mail for that domain.

You can find out more about spf at <>

Lewis Butler, Owner
240 S Broadway #203, 80209
mobile: 303.564.2512  fx: 303.282.1515
AIM/ichat: covisp xdi:

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