Configure multiple SendGrid accounts on Linux
2 minute read
14 Apr 2017
This guide explains how to configure two or more SendGrid accounts on Linux running Postfix mail server.
To make this work we’ll use Postfix’s per-sender SASL passwords configuration, which allows switching credentials based on the envelope sender address (this is different from the “From” address, as will be explained below)
Before you begin make sure:
- you have the correct user/password for all SendGrid accounts
- you have SSH access with elevated permissions (login with
Edit Postfix main configuration file:
sudo nano /etc/postfix/main.cf
Make sure there are no other SendGrid settings, and add the following at the end of the file:
relayhost = [smtp.sendgrid.net]:587 smtp_sasl_auth_enable = yes smtp_sender_dependent_authentication = yes smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd smtp_sasl_mechanism_filter = plain smtp_sasl_security_options = noanonymous smtp_tls_security_level = encrypt header_size_limit = 4096000
Now create the
/etc/postfix/sasl_passwd passwords file:
sudo nano /etc/postfix/sasl_passwd
sasl_passwd file is where the domain-credentials binding is done. Consider the following example:
# Per-sender authentication @mydomain.com my_sendgrid_user:my_sendgrid_password @anotherdomain.com another_sendgrid_user:another_sendgrid_password # ...add as many domains as you need... # Login information for the default relayhost [smtp.sendgrid.net]:587 default_sendgrid_user:default_sendgrid_password
In the above example if the sender address ends in
@mydomain.com it will use the
my_sendgrid_user account, if it ends in
@anotherdomain.com will use the
If none of these match it will use the
@domainscan be anything, but is recommended to use something easily identifiable, like the actual domain of the site (example:
@training.wmtek.com) These domains are used internally, between PHP and Postfix, so they are different than the actual
Fromaddress that the recipient will see.
Configure Site Stacker
For each Site Stacker installation that should use a different SendGrid account than the default one, we need to add an additional parameter in the
email.php config file.
email.php config file on each installation:
sudo nano [sitestacker_root]/App/Config/email.php
$default configuration add the
additionalParameters option. The following example assumes we’re configuring the beforementioned
public $default = array( 'transport' => 'Mail', 'from' => array('email@example.com' => 'SiteStacker'), 'log' => 'email', 'additionalParameters' => '-firstname.lastname@example.org' );
Note: There is no space between
The value for the
additionalParameters is where we declare the sender address for the current installation. The most important thing to note is the use of
@mydomain.com, this is required to match one of the domains declared in the
sitestacker part of the sender address can be anything.
All is left is to make the Postfix configuration active:
sudo postmap /etc/postfix/sasl_passwd sudo service postfix reload
Done. Thank you!