cd /etc/mail
cp sendmail.cf sendmail.cf.orig
cp sendmail.mc sendmail.mc.orig
mkdir -m 700 -p /etc/mail/auth
touch /etc/mail/auth/auth-info
cd /etc/mail/auth
makemap hash auth-info < auth-info
chmod 0600 /etc/mail/auth/*
Edit /etc/mail/sendmail.mc
define(`RELAY_MAILER_ARGS', `TCP $h 587')dnl
define(`ESMTP_MAILER_ARGS', `TCP $h 587')dnl
define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
FEATURE(`authinfo',`hash /etc/mail/auth/auth-info')dnl
TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')
Save the file and make the sendmail.cf:
cd /etc/mail
m4 sendmail.mc > sendmail.cf
Restart sendmail service