You do not need to have sendmail running in daemon mode to send and receive email, and unless you have a constant network connection, you probably cannot run sendmail in daemon mode. Daemon mode means that sendmail is constantly listening on a network connection waiting to receive mail.
If you disable daemon mode, Bastille will ask you if you would like to run sendmail every few minutes to process the queue of outgoing mail. Most programs which send mail will still do so immediately, and processing the queue will take care of transient errors.
If you receive all of your email via a POP/IMAP mailbox provided by your ISP, you may have no need of daemon-mode sendmail, unless you're running a special fetchmail-style POP/IMAP based retrieval program. For instance, you can turn daemon mode off if you read your mail via Netscape's common POP/IMAP read functionality. The only reason to run sendmail in daemon mode is if you are running a mail server. |