I'm running Ubuntu on AWS and am using their SES (Simple Email Service) and sSmtp to email logs since that is the only need for email on the server.

I have ssmtp sent up and everything works, except emails sent from cron jobs are being rejected due to the From: address. SES requires that the From: and To: email addresses be verified, but the email sent from cron and just root, not root@mydomain.com.

Is there a way to set the full email address that cron uses as the From: address, or is there a way to get ssmtp to rewrite the From: when it is a just a name with no domain?

My ssmtp.conf looks like this:



  • 1
    It answers one part of my question, but doesn't address the part about is ssmtp can be configured to deal with naked username. Apr 5, 2013 at 21:38

2 Answers 2


cron is using the sendmail command to send mails. Normally the mailserver is appending the domain so in your case ssmtp would need to to that.

I never used sSMTP before but it's sender rewriting seems pretty strange. I looked at the source code and there is a file /etc/ssmtp/revaliases.

The example lists this:

# sSMTP aliases
# Format:       local_account:outgoing_address:mailhub
# Example: root:your_login@your.domain:mailhub.your.domain[:port]
# where [:port] is an optional port number that defaults to 25.

In your case probably:

  • The revaliases seems to be used for the To: address. I do have it set up as you've suggested. Apr 5, 2013 at 21:54
  • No, it is used for the FROM address. Try setting the FromLineOverride to NO. Apr 5, 2013 at 22:02
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    For what ever reason, setting the FromLineOverride to NO causes SES to reject the emails. I am not sure why, but I found this advice when first setting it up and it solved the problem. Apr 5, 2013 at 23:25
  • 1
    This answer is correct: configuring /etc/ssmtp/revaliases per @Sebastian's explanation, and setting FromLineOverride=NO in /etc/ssmtp/ssmtp.conf results in the sent emails being accept by Amazon SES. Nov 13, 2014 at 17:17

As it doesn't seem to be possible to change the From: address that cron sends from in Ubuntu, I have found a hacky solution. It's probably not the best way, but it does seem to work.

When ssmtp is installed, it creates a link from /usr/sbin/sendmail to /usr/sbin/ssmtp. What I did was delete the link and created a sendmail file that contains the following:

sed "s/From: root /From: root@mydomain.com /" | /usr/sbin/ssmtp $*

Now any mail sent from root will get rewritten to root@mydomain.com

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