Sendmail Installation and Operation Guide
SMM:08-21
/usr/sbin/sendmail -bi
If you have multiple aliases databases specified, the -bi flag rebuilds all the database
types it understands (for example, it can rebuild NDBM databases but not NIS databases).
2.6.2. Potential problems
There are a number of problems that can occur with the alias database. They all result
from a sendmail process accessing the DBM version while it is only partially built. This can
happen under two circumstances: One process accesses the database while another process is
rebuilding it, or the process rebuilding the database dies (due to being killed or a system crash)
before completing the rebuild.
Sendmail has three techniques to try to relieve these problems. First, it ignores interrupts
while rebuilding the database; this avoids the problem of someone aborting the process leaving a
partially rebuilt database. Second, it locks the database source file during the rebuild -- but that
may not work over NFS or if the file is unwritable. Third, at the end of the rebuild it adds an
alias of the form
@: @
(which is not normally legal). Before sendmail will access the database, it checks to insure that
this entry exists
11
.
2.6.3. List owners
If an error occurs on sending to a certain address, say "x", sendmail will look for an alias
of the form "owner-x" to receive the errors. This is typically useful for a mailing list where the
submitter of the list has no control over the maintenance of the list itself; in this case the list
maintainer would be the owner of the list. For example:
unix-wizards: eric@ucbarpa, wnj@monet, nosuchuser,
sam@matisse
owner-unix-wizards: unix-wizards-request
unix-wizards-request: eric@ucbarpa
would cause "eric@ucbarpa" to get the error that will occur when someone sends to unix-wiz-
ards due to the inclusion of "nosuchuser" on the list.
List owners also cause the envelope sender address to be modified. The contents of the
owner alias are used if they point to a single user, otherwise the name of the alias itself is used.
For this reason, and to obey Internet conventions, the "owner-" address normally points at the
"-request" address; this causes messages to go out with the typical Internet convention of using
``list-request'' as the return address.
2.7. User Information Database
This option is deprecated, use virtusertable and genericstable instead as explained in
cf/README. If you have a version of sendmail with the user information database compiled in, and
you have specified one or more databases using the U option, the databases will be searched for a
user:maildrop entry. If found, the mail will be sent to the specified address.
2.8. Per-User Forwarding (.forward Files)
As an alternative to the alias database, any user may put a file with the name ".forward" in his
or her home directory. If this file exists, sendmail redirects mail for that user to the list of addresses
11
The AliasWait option is required in the configuration for this action to occur. This should normally be specified.