Description of problem:

Failed attempts to run 'sudo' result in a mail from root. However, 'man sudoers' mentions that the default should be to send mail as if coming from the user:
     mailfrom      Address to use for the “from” address when sending warning
                   and error mail.  The address should be enclosed in double
                   quotes ("") to protect against sudo interpreting the @
                   sign.  Defaults to the name of the user running sudo.

My reason for wanting the user's mail as sender is, so the system manager (me) can reply to the mail and explain to the user why it didn't work, and other custom suggestions that cannot be included in the default 'lecture'

So, this looks like a discrepancy between the program and its documentation. Fixing the program would be best, but if that is not possible, the documentation may have to be patched to match.

Version-Release number of selected component (if applicable):
sudo-1.8.15-1.fc23.x86_64

How reproducible:

Run 'sudo' as a user that is not authorized in /etc/sudoers

Steps to Reproduce:
1. Install sudo
2. As a non-root user (eg joe), run something like 'sudo bash'
3. As root, read the mail with the "SECURITY information"

Actual results:
The mail to root will also be from root, not from the user joe, so a direct reply is not possible.

Expected results:
Mail from the user that invoked sudo, as documented.

Additional info:
Even hardcoding 'mailfrom' in /etc/sudoers doesn't seem to make a difference, although 'sudo -V' run as root will report this setting if it is present.