¿Como se puede hacer funcionar al comando mail con ssmtp?

# /etc/ssmtp.conf -- a config file for sSMTP sendmail.
#

# The person who gets all mail for userids < 1000
# Make this empty to disable rewriting.

#root=postmaster
root=kapyderi.juanjoATgmail.com (HE SUSTITUIDO @ POR "AT")

# The place where the mail goes. The actual machine name is required
# no MX records are consulted. Commonly mailhosts are named mail.domain.com
# The example will fit if you are in domain.com and your mailhub is so named.

#mailhub=mail
mailhub=smtp.gmail.com:587

# Example for SMTP port number 2525
# mailhub=mail.your.domain:2525
# Example for SMTP port number 25 (Standard/RFC)
# mailhub=mail.your.domain
# Example for SSL encrypted connection
# mailhub=mail.your.domain:465

# Where will the mail seem to come from?

rewriteDomain=

# The full hostname

#hostname=_HOSTNAME_
UseSTARTTLS=YES
hostname=kapyderi.juanjo
AuthUser=kapyderi.juanjoATmail.com (HE SUSTITUIDO @ POR "AT")
AuthPass=**************** (LA MIA CLARO)

# Set this to never rewrite the "From:" line (unless not given) and to
# use that address in the "from line" of the envelope.

#FromLineOverride=YES

# Use SSL/TLS to send secure messages to server.

#UseTLS=YES

# Use SSL/TLS certificate to authenticate against smtp host.

#UseTLSCert=YES

# Use this RSA certificate.

#TLSCert=/etc/ssl/certs/ssmtp.pem

# Get enhanced (*really* enhanced) debugging information in the logs
# If you want to have debugging of the config file parsing, move this option
# to the top of the config file and uncomment

#Debug=YES

Y mi otro fichero

# sSMTP aliases
#
# Format: local_account:outgoing_address:mailhub
#
# Example: root:your_login@your.domain:mailhub.your.domain[:port]
# where [:port] is an optional port number that defaults to 25.

root:kapyderi.juanjoATgmail.com:smtp.gmail.com:587
mainuser:kapyderi.juanjoATgmail.com:smtp.gmail.com:587

A ver si tu ves alguna diferencia en el contenido, jajaja

Por otro lado, me puedes indicar todos los paquetes que has descargado para configurarlo ¿?, me refiero a sendmail u otro similar que requiera ser utilizado como pasarela.

Saludos y gracias por la paciencia!!!