D.5 The > Option

Prior to V8, Sun's sendmail used the R option to cause all mail to be automatically routed to a mail hub machine. V8 sendmail coopted the R option for its own use, so Sun had to switch the option name to >. The > option is available only with V6/Sun, and above, configuration files.

The > option is used like this:

O>mailhub

If the entire > option is omitted, all mail is delivered locally. If mailhub is present and if it is not the name of the local host, all mail is forwarded to that machine for delivery. If the mailhub is omitted and if /var/mail is NFS mounted, all mail is forwarded to the host that is exporting /var/mail. The name of the mailhub, no matter how it was determined, is assigned to the $K macro for use by rule sets.

Be aware that by setting and using this option, you are letting sendmail's internals make all the decisions for you. If you prefer more control, investigate the nullclient FEATURE described in Section 19.6.20, FEATURE(nullclient).

The > option is safe. When it is specified from the command line, sendmail retains its root privilege.