Steps to setup mailtrap.io with your sendmail in ubuntu
Install sendmail and mailutils in ubuntu 'apt-get install sendmail mailutils'
In the terminal go into root prompt with
sudo -s
Go to the /etc/mail folder
Make a backup of your original sendmail.cf and sendmail.mc files
Make a copy of the sendmail.mc file to sendmail-mailtrap.mc file with the command
cp sendmail.mc sendmail-mailtrap.mc
Make a directory called auth in the /etc/mail with command
mkdir /etc/mail/auth
Inside the auth directory type the command
echo 'AuthInfo:mailtrap.io "U:root" "I:mailtrap-username" "P:mailtrap-password' > mailtrap-info
Then type the following command
makemap -r hash mailtrap-info.db < mailtrap-info
Go back to the /etc/mail folder and open the sendmail-mailtrap.mc file with your fav text editor
And paste this code before the MAILER_DEFINITIONS line
dnl # GMAIL FORWARDING
define(`SMART_HOST',`[mailtrap.io]')dnl
define(`RELAY_MAILER_ARGS', `TCP $h 2525')dnl
define(`ESMTP_MAILER_ARGS', `TCP $h 2525')dnl
define(`confAUTH_OPTIONS', `A p')dnl
TRUST_AUTH_MECH(`EXTERNAL DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
define(`confAUTH_MECHANISMS', `EXTERNAL GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
FEATURE(`authinfo',`hash -o /etc/mail/auth/mailtrap-info.db')dnl
Make sure the port number given in the settings of your mailtrap account matches the one you are defining here in the RELAY_MAILER_ARGS and ESMTP_MAILER_ARGS constants
After this save the file and type this command
m4 sendmail-mailtrap.mc > sendmail.cf
If you are done till here restart the sendmail service with
service sendmail restart
To test if send mail is working with mailtrap try the command
mail -s "Testing new Gmail Forwarding" [email protected]
Blah Blah Blah
^D (This is control+d)
You should be able to see this mail in your mailtrap inbox