Local admin mail is stored in /var/mail in a file named after the account name. Each email is appended to the begining of the file, so the file size continues to increase with each email received. To remove all email delete the file. From CLI, cd /var/mail then delete the mail by removing the file:
If you do not want to store admin mail locally, you have two options:
1) Send admin mail off the firewall to an external account.
2) Send admin mail to /dev/null.
For either option, edit the /etc/mail/aliases file. In this file, locate the following lines:
# Pretty much everything else in this file points to "root", so
# you would do well in either reading root's mailbox or forwarding
# root's email from here
Edit the "root: admin_account" line and enter either an external email address, or enter "/dev/null" to not store mail locally. For example,
root: firstname.lastname@example.org (to send mail to an external account)
root: /dev/null (will not store mail locally or send to an external address)
Then run "newaliases" or "cf sendmail rebuild" from CLI.
Storing mail locally will eventually cause the partition to fill and force the firewall into failure mode. It is recommended to deliver mail to an external account or to write mail to /dev/null.
Many thanks for this very complete answer.
I did try mv the file but the SecureOS filetype enforcement prevented me from doing this.
I'll just delete the file and setup the alias as you advise.