How to Use Google SMTP Relay with Sendmail

Check to see if TLS is enabled:
# sendmail -d0.1 -bv root

Make a certs directory:
# mkdir /ect/mail/certs
# cd /ect/mail/certs

Create SSL certificates:
# openssl req -new -x509 -keyout cakey.pem -out cacert.pem -days 3650
// password, all left default
# openssl req -nodes -new -x509 -keyout sendmail.pem -out sendmail.pem -days 3650

copy certificates from system to mail directory:
# cp /etc/pki/tls/certs/ca-bundle.crt /etc/mail/certs

Stop sendmail services prior to making changes:
# service sendmail stop

Create authentication table:
# vim /etc/mail/authinfo
---- "U:root" "" "P:Katie2000" "M:PLAIN" "U:root" "" "P:Katie2000" "M:PLAIN"
makemap hash /etc/mail/authinfo < /etc/mail/authinfo

Defined "SMART_HOST" information:
# vim /etc/mail/
FEATURE(`authinfo',`hash /etc/mail/authinfo.db')dnl
define(`SMART_HOST', `')dnl
define(`RELAY_MAILER_ARGS', `TCP $h 587')
define(`ESMTP_MAILER_ARGS', `TCP $h 587')
define(`CERT_DIR', `/etc/mail/certs')
define(`confCACERT_PATH', `CERT_DIR')
define(`confCACERT', `CERT_DIR/ca-bundle.crt')
define(`confCRL', `CERT_DIR/ca-bundle.crt')
define(`confSERVER_CERT', `CERT_DIR/sendmail.pem')
define(`confSERVER_KEY', `CERT_DIR/sendmail.pem')
define(`confCLIENT_CERT', `CERT_DIR/sendmail.pem')
define(`confCLIENT_KEY', `CERT_DIR/sendmail.pem')
# m4 /etc/mail/ > /etc/mail/

Start the email service:
# service sendmail start


php /home/www/kimconnect/testmail.php

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