#Mac smtp upgrade#
#Mac smtp verification#

Create a password file for Postfix to use in logging in to your Fastmail account, at /etc/postfix/sasl_passwd.

Or just make it a special New Year’s Eve tradition. To be safe you might want to put that in a cron job. $ sudo security find-certificate -a -p /System/Library/Keychains/SystemRootCertificates.keychain > /etc/postfix/ssl/ca-bundle.crt

#Mac smtp verification#

This step is important because I’ve found that the server certificate Fastmail uses from Digicert is not included in the default SSL cert bundle available to Postfix, and you’ll get errors like “certificate verification failed for ” that prevent the mail from being relayed. Generate a modern certificate bundle that Postfix can use, using the macOS keychain ( share).Smtp_sasl_tls_security_options = noanonymous Smtp_sasl_mechanism_filter = PLAIN, LOGIN Smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd Edit /etc/postfix/main.cf and add these lines to the end:.

Most of these steps are derived from this nice compilation of steps that applies to macOS Sierra through Mojave. I recently went through the process again, so thought I’d write it up here in case it’s helpful to others. So I’ve come to document it pretty heavily for my own reference.

#Mac smtp upgrade#

In reality, I’ve found it to be a somewhat fragile configuration, and rarely does it survive a macOS upgrade or switch to a new computer. The notion of relaying email through a specific provider is built in to the Postfix mail transport agent that comes with macOS, so in theory it’s not a big deal to set up.

This especially makes sense since most of the email from my OS is going straight to my inbox hosted at Fastmail. Instead, I relay all outgoing mail sent from macOS through my email provider, Fastmail (affiliate link). It’ll likely fail, it’s not secure, and there are better ways. When my Mac laptop tries to send me email - the output of a cron job, for example - by default it ends up in a local mailbox file that I never check. I want the mail to get to my regular email account, but I don’t want it to relay that message through whatever random ISP I might be connected to at any given time, or over the open internet.