I am using PHP to send e-mail through Sendmail. Specifically, I am using the mail( ) function. I have been using this function for years on a web host, but now I am trying to use my own server. (Slackware Linux 7).
When I send a message, it is not delivered, and I get a message in my root mailbox stating, among other things, the following error:
" ----- The following addresses had permanent fatal errors -----
(reason: 501 5.1.8 <email@example.com>... Domain of sender address
firstname.lastname@example.org does not exist)"
Do I have to set something up in order to send mail from my Linux box? For instance, do I have to set up an SMTP server? If so, how do I do that? I'll give 300 points for anyone who can help me out! (If you live close, I'll even buy you a pizza!)