Sendmail and "Proper Authentication"

[Nicholas Ink]

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