Sendmail and "Proper Authentication"

[Ted Mittelstaedt]

Go into sendmail.cf

set DSmail.example.org

(where mail.example.org = the hostname of your ISP's mailserver)

Let me put it this way for you.  ISP's these days are taking a lot of
steps to prevent people from setting up little servers in their homes
and directly sending SMTP mail from them.  One way of doing this
is by not setting up PTR records for IP numbers assigned to end
users.  Users can setup hostnames in their own domains at places
like dydns.org and such, and have all the forward records they want -
but more and more large ISP's like gmail are refusing to accept mail
from IP addresses without PTR records.

There are many other ways besides the admittedly crude method
above.  The upshot is that it's better for the rest of us on the
Internet to force end users as much as possible to relay outbound
mail through their ISP's.

If you want to directly process outbound mail yourself, then
your going to have to do a LOT more reading up on current
spamfighting methods before you attempt to do this.

Receiving inbound e-mail is the easy part.  No ISP cares if
any of their customers setup to receive mail directly.  (or at
least, no decently run ones does)  Hell, if you take mail
directly it frees up their CPU power and disk space on their
mailserver.

But sending it is a whole different animal.  Within another 5
years it is going to get to the point that the only inter-domain
e-mail that will flow on the Internet is from ISP to ISP.  Save
yourself a huge headache and pass your outbound mail to
your ISP's mailserver, that's what it's there for.

Ted

----- Original Message ----- 
From: "Nicholas Ink" <nicholasink at gmail.com>
To: <freebsd-questions at freebsd.org>
Sent: Wednesday, August 23, 2006 8:50 PM
Subject: Sendmail and "Proper Authentication"


> Hello all.
>
> I have been using FreeBSD for several months now, and have been
> configuring it as a multipurpose server.  I've installed a web server,
> database, and a handful of other utilities.  I also have now been
> attempting for some time to configure an e-mail service - with
> Sendmail.
>
> Although everything seems to work fine with receiving e-mail, I have
> had significant trouble with sending it.  For example, I have been
> trying to send an e-mail from my FreeBSD server to my Gmail account.
> The first problem I experienced was that there a host name lookup
> failure for "gmail.com," which I have subsequently corrected by adding
> the line:
>
> gmail.com       smtp:[smtp.gmail.com]
>
> to /etc/mail/mailertable.  However, there is still a problem, when I
> try to send an e-mail, /var/log/maillog says:
>
>
> Aug 23 23:18:08 arches sm-mta[1049]: k7O3I7K2001049:
> from=<nink at XXXXXXXX.xxx>, size=397, class=0, nrcpts=1,
> msgid=<44ED1A6F.1090009 at XXXXXXXX.xxx>, proto=ESMTP, daemon=IPv6,
> relay=localhost [IPv6:::1]
>
> Aug 23 23:18:16 arches sm-mta[1051]: STARTTLS=client,
> relay=gmail-smtp.l.google.com., version=TLSv1/SSLv3, verify=FAIL,
> cipher=DES-CBC3-SHA, bits=168/168
>
> Aug 23 23:18:16 arches sm-mta[1051]: k7O3I7K2001049:
> to=<nicholasink at gmail.com>, ctladdr=<nink at XXXXXXXX.xxx> (1007/0),
> delay=00:00:08, xdelay=00:00:08, mailer=smtp, pri=30397,
> relay=gmail-smtp.l.google.com. [66.249.83.111], dsn=5.0.0,
> stat=Service unavailable
>
> Aug 23 23:18:16 arches sm-mta[1051]: k7O3I7K2001049: k7O3IGK2001051:
> DSN: Service unavailable
>
>
> where arches is my host name.  I can't understand why it continues to
> say "Service unavailable" when I know Gmail is not experiencing any
> downtime or anything else.  Is this some sort of spam filter?  Any
> help would be greatly appreciated!  Thanks!
>
>   Sincerely,
>   Nicholas Ink
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