I am looking for a way to fix a problem...

When I disable the user nobody (as below details), users
can not use formmail, or forums that send out a 'someone has replyed' to your post message, but with it on, I know I am open
to allowing 'nobody' to send messages.. Is there any way
to turn it on, and still allow forums and formmail to work for users?

In one other case, it would not let a user send out email
from his own account, but I did not get full details on
how that came about, just what I was told really.


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Prevent the user 'nobody' from sending out mail to remote addresses (php and cgi scripts generally run as nobody if you are not using phpsuexec and suexec respectively.)
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The option in WHM is only used when you have phpsuexec installled and suexec enabled. You can install phpsuexec by re-compiling Apache in WHM (Update Apache link and then select "PHP suEXEC Support"). There are disadvantages of using phpsuexec though which I'm sure if you search these forums, you will find them. But to prevent the user "nobody" from sending emails, that is what you will need to do.