A default file will be installed in /etc. The default configuration should work for most SMTP-only sites (Simple Mail Transfer Protocol) . It will not work for UUCP (Unix to UNIX Copy Protocol) sites; you will need to generate a new if you must use UUCP mail transfers.

NotePlease Note

Although SMTP servers are supported automatically, IMAP (Internet Message Access Protocol) servers are not. If your ISP uses an IMAP server rather than an SMTP sever, you must install the IMAP package. Without it, your system won't know how to pass information to the IMAP server or retrieve your mail.

To generate a new, you will need to install m4 and the sendmail source package. Read the README file in the sendmail sources for more details on creating sendmail configuration files. Also, O'Reilly & Associates publishes a good sendmail reference entitled sendmail, by Bryan Costales.

One common sendmail configuration is to have a single machine act as a mail gateway for all the machines on your network. For instance, at Red Hat we have a machine that does all our mail. On that machine we simply need to add the names of machines for which will handle mail to /etc/ Here is an example:

# - include all aliases for your machine
# here.

Then on the other machines, torgo, poodle, and devel, we need to edit /etc/ to "masquerade" as when sending mail, and to forward any local mail processing to Find the DH and DM lines in /etc/ and edit them as such:

# who I send unqualified names to
# (null means deliver locally)
# who gets all local email traffic
# who I masquerade as (null for no masquerading)

With this type of configuration, all mail sent will appear as if it were sent from, and any mail sent to or the other hosts will be delivered to

Please be aware that if you configure your system to masquerade as another any e-mail sent from your system to your system will be sent to the machine you are masquerading as. For example, in the above illustration, log files that are periodically sent to by the cron daemon would be sent to .