Smart Host: Relaying Mails from Sendmail to Gmail

There are cases wherein the mails that are being sent from server does not arrive at the recipient's inbox. One possible cause is that the mail was considered a spam. One solution that can be done, dealing with this issue, is to relay the emails to a trusted SMTP host say like Gmail. How are we going to do it here is how.

First you need to have sendmail a native MTA for Linux. Here are the packages you need to have

- sendmail
- senmail-cf
- sendmail-devel

All of these packages can be installed via yum.

Next enable the smart host feature on sendmail. Open the sendmail configuration file.

vi /etc/mail/sendmail.mc

Change this:

dnl define(`SMART_HOST',`smtp.gmail.com')dnl

to:

define(`SMART_HOST',`smtp.gmail.com')dnl

Next add this entry before the entry of smart host.

FEATURE(`authinfo',`hash /etc/mail/auth/client-info')dnl

If you don't have an /etc/mail/auth directory, as root, create one like this:

# mkdir -p /etc/mail/auth
# chmod 700 /etc/mail/auth

You won't have the next client-info files so you'll have to create it (with you favorite Unix editor). Change the permissions on the client-info file like this:

# chmod 600 client-info

So using my user_id@gmail.com email ID and password I made the following entry in /etc/mail/auth/client-info:

# cat /etc/mail/auth/client-info
AuthInfo:smtp.gmail.com "U:smmsp" "I:user_id" "P:password" "M:PLAIN"
AuthInfo:smtp.gmail.com:587 "U:smmsp" "I:user_id" "P:password" "M:PLAIN"

Yes, password is plain text. It is possible to encode the password but I don't have those instructions here.

Remember to replace user_id with your Gmail email ID (your email addresse without the @gmail.com) and password with your email password. Also make sure that the client-info file has a

How to compile it into a db file:

# cd /etc/mail/auth
# makemap -r hash client-info.db <> sendmail.cf

And lastly restart sendmail:

# /sbin/service sendmail restart

Now you can test it....

Hope you find this useful. Thanks, Cheers and God Bless!!!!