One of the main benefits of sympathetic pregnancy insomnia is that I am able to get a jump on all these little projects that I had been meaning to take care of but never had the motivation. Configuring sendmail to use Yahoo Mail as a relay to handle outbound mail from Apache is one of those projects I’ve put off for far to long. Thanks to two HowTos I managed to knock this out in a couple of minutes.

sudo apt-get install sendmail

sudo /etc/init.d/sendmail stop

sudo nano /etc/mail/authinfo and add the following:

AuthInfo:yahoo.com “U:babydaddy@your_ATT_Domain” “I:babydaddy@your_ATT_Domain” “P:password_here” “M:PLAIN”
AuthInfo: “U:babydaddy@your_ATT_Domain” “I:babydaddy@your_ATT_Domain” “P:password_here” “M:PLAIN”

sudo chmod 660 /etc/mail/authinfo to lock it down.
sudo makemap hash /etc/mail/authinfo < /etc/mail/authinfo to make the map file.
sudo nano /etc/mail/sendmail.mc and look for or add the following lines:

define(`confAUTH_OPTIONS’, `A’)dnl
define(`confAUTH_MECHANISMS’, `LOGIN PLAIN DIGEST-MD5 CRAM-MD5′)dnl
TRUST_AUTH_MECH(`LOGIN PLAIN DIGEST-MD5 CRAM-MD5′)dnl
FEATURE(`authinfo’,`hash -o /etc/mail/authinfo.db’)dnl
define(`SMART_HOST’, `esmtp:[smtp.sbcglobal.yahoo.com]‘)dnl

sudo cp /etc/mail/sendmail.cf /etc/mail/sendmail.cf.bak because you can never to too sure.

sudo make /etc/mail/sendmail.cf -C /etc/mail to rebuild your sendmail.cf.
sudo /etc/init.d/sendmail start

To test your set up create a text file that at least includes a To and a Subject:To:ServerMonkey@foo
Subject:Linux Rules Windows Drools

sudo sendmail -Am -v -t < your_text_file to shoot a copy out to yourself.

You should see something like this:

babydaddy@your_ATT_Domain… Connecting to smtp.sbc.mail.yahoo4.akadns.net. via esmtp…
220 smtp110.sbc.mail.re2.yahoo.com ESMTP
>>> EHLO your_domain
250-smtp110.sbc.mail.re2.yahoo.com
250-AUTH LOGIN PLAIN XYMCOOKIE
250-PIPELINING
250 8BITMIME
>>> AUTH PLAIN xxxxxxxxxxxxxxxxxxxxxxxx
235 ok, go ahead (#2.0.0)
>>> MAIL From: AUTH=root@your_domain
250 ok
>>> RCPT To:
>>> DATA
250 ok
354 go ahead
>>> .
250 ok 1166057377 qp 49511
babydaddy@your_ATT_Domain… Sent (ok 1166057377 qp 49511)
Closing connection to smtp.sbc.mail.yahoo4.akadns.net.
>>> QUIT
221 smtp110.sbc.mail.re2.yahoo.com

sudo nano /etc/php5/apache2/php.ini so that it knows where sendmail hangs out.

Find the line with sendmail_path, delete the ; and edit it to read:

sendmail_path = /usr/sbin/sendmail -i -t

sudo /etc/init.d/apache2 reload to make the changes stick.

Sendmail is now configured to use Yahoo as a relay! Now, ideally you should be able to massage this to use any external SMTP server that allows plain text authentication.

Gratefully cribbed from here and here.