The sendmail configuration in Realm Linux is a bit different than what you may be used to from Red Hat products. It is important that you understand these differences if you need your machine to handle any thing more than sending email. The most useful sendmail configuation changes can be done with the RealmConfig tool.

The most important difference in the sendmail setup for Realm Linux is that all mail received, except for the root user, is considered mail to an NCSU realm user or alias. After all, a Realm Linux machine did receive the mail in question. As such, this mail will be forwarded to NCSU's mail system and delivered to a user's NCSU mailbox or bounced. This also includes mail received over the loopback interface that sendmail listens on.

If you have a local account or a realm account that you wish to collect mail for locally on the Realm Linux machine you need to tell sendmail about this user ID. Do this with RealmConfig. First, select the check box to receive mail locally. Secondly, add the user ID to the local mail users list. You may also edit the local mail users list by hand. The file name is /etc/mail/local-mail-users. Lastly, remember to restart sendmail.

	Note
	The RealmConfig tool does not modify your local firewall settings. If you chose to receive mail locally then you must also check to make sure that the firewall will allow incoming traffic on port 25 for SMTP.

RealmConfig also contains a setting for the sendmail masquerade option. This changes the domain where your mail appears to come from. Using the default of unity.ncsu.edu is strongly recommended.