Use exim4 as smarthost SMTP server.(UBUNTU) apt-get install exim4 su - $ dpkg-reconfigure exim4-config General type of mail configuration: mail sent by smarthost; received via SMTP or fetchmail System mail name: localhost Ip Address to listen on: 127.0.0.1 Other destinations~: yourdyndns.domain.com Machines to Relay for: IP address or hostname of the outgoing smarthost: smtp.gmail.com::587 Hide local mail name in outgoing mail: No Keep number of DNS queries minimal: No Delivery method for local mail: mbox format in /var/mail/ Split configuration into small files: Yes vi /etc/exim4/passwd.client gmail-smtp.l.google.com:user_relay@gmail.com:password_relay *.google.com:user_relay@gmail.com:password_relay smtp.gmail.com:user_relay@gmail.com:password_relay $ chmod 640 /etc/exim4/passwd.client $ chown root:Debian-exim /etc/exim4/passwd.client $ vi /etc/exim4/email-addresses root@localhost: user_relay@gmail.com $ chmod 640 /etc/exim4/email-addresses 5. Verifing Exim config. $ vi /etc/exim4/update-exim4.conf dc_eximconfig_configtype='smarthost' dc_other_hostnames='yourdyndns.domain.com' dc_local_interfaces='127.0.0.1' dc_readhost='yourdyndns.domain.com' dc_relay_domains=" dc_minimaldns='false' dc_relay_nets=" dc_smarthost='smtp.gmail.com::587' CFILEMODE='644' dc_use_split_config='true' dc_hide_mailname='false' dc_mailname_in_oh='true' dc_localdelivery='mail_spool' 6. restart service MTA. $ /etc/init.d/exim4 restart (RedHat)centos-fedora yum install exim So what to do is: edit "/etc/exim/exim.conf", add: # routers section send_via_gmail: driver = manualroute domains = ! +local_domains transport = gmail_smtp route_list = * gmail-smtp.l.google.com # transports section gmail_smtp: driver = smtp port = 587 hosts_require_auth = gmail-smtp.l.google.com hosts_require_tls = gmail-smtp.l.google.com # authenticators section gmail_login: driver = plaintext public_name = LOGIN client_send = : youraccount@gmail.com : yourpassword [root@localhost ~]# service exim start