Mini-HOWTO:
Using Sendmail with a Smart Gateway with SBC DSL

SBC/Yahoo's DSL service uses a number of tricks to keep you from using their SMTP server as a smart gateway from your Linux box. This includes spoofing their MX records to route the SMTP gateway they give to a host called nomail.yahoo.com that rejects all mail, and requiring authentication. This can be a pain to configure. Hence this web page.

Note that these instructions are based on the configuration of sendmail 8.12 on Red Hat Linux 8.0. Of particular note, versions of sendmail prior to 8.12 are configured differently. It goes without saying that you need to be logged in as root to perform this setup.

First, you need to have sendmail set up as your default mailer. Select the System Settings | Mail Transport Agent Switcher in the GUI to verify. You also need to have the sendmail-cf RPM installed. This can be downloaded from rhn.redhat.com if you don't have it (my computer did not get it installed by default).

Next, configure sendmail. Go to /etc/mail and modify the sendmail.mc file as follows -- AFTER YOU MAKE A BACKUP OF THE ORIGINAL:

• Uncomment SMART_HOST and make the value `esmtp:[smtp.sbcglobal.yahoo.com]' or whatever they told you your SMTP server was.
• Uncomment the TRUST_AUTH_MECH and define(`confAUTH_MECHANISMS' lines. Be sure that they include the value PLAIN
• In with the rest of the features, add a line reading FEATURE(`authinfo',`hash -o /etc/mail/authinfo.db')dnl

Regenerate the sendmail.cf file by running m4 as follows: m4 sendmail.mc > sendmail.cf

If you get an error about /usr/share/sendmail-cf/m4/cf.m4 missing, that means you don't have the sendmail-cf package installed.

Next create a file called /etc/mail/authinfo. Put two lines in it as follows:

AuthInfo:yahoo.com "U:yoursbcusername" "P:yoursbcpassword" "M:PLAIN"
AuthInfo: "U:yoursbcusername" "P:yoursbcpassword" "M:PLAIN"

Be careful, if you have this but route mail to anything other than the SBC gateway, you'll probably be sending your SBC login info. Your SBC username is probably something like something@sbcglobal.net.

Create the authinfo database by running the command makemap hash /etc/mail/authinfo.db < authinfo

Restart sendmail. You can do this with the command `/sbin/service sendmail stop' followed by `/sbin/service sendmail start' on Red Hat. Otherwise, just kill sendmail and start it up manually. I like verbose logging. So try `/usr/lib/sendmail -bd -OLogLevel=14'

Try to send email. If it doesn't reach its destination, look in the log file. On Red Hat, this is probably /var/log/maillog. If you get a bounce message, look at it to assist in diagnostics.

Hope this helps. Good Luck!

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