sendmail, 4th Edition

AutoRebuildAliases

Auto-rebuild the aliases database Deprecated

Beginning with V8.10 sendmail, it was discovered that auto-rebuilding the aliases database held the potential for a denial-of-service attack. If a user could kill sendmail during a rebuild, the aliases database could be left in an incomplete state, resulting in possible lost and misdirected email. As a consequence, this AutoRebuildAliases option is deprecated. Although it is present in V8.10 and V8.11, you should not use it. This option has been eliminated since V8.12.

Prior to V8.10 sendmail, the need to auto-rebuild the aliases database was determined by comparing the modification time of the aliases source file, as defined by the AliasFile option (AliasFile on page 970), to the modification time of the corresponding aliases.pag and aliases.dir, or aliases.db, database files. If the source file was newer and if this AutoRebuildAliases option was set, sendmail attempted to rebuild the aliases database. If this option was not set, sendmail printed the following warning and used the information in the old database:

Warning: alias database fname out of date

Here, fname is the name of the source file. If you wish to set this to AutoRebuildAliases, despite the risk, be sure that the AliasWait option (AliasWait on page 973) is also declared and given a nonzero time argument. (Note that file locking, to prevent simultaneous rebuilds, is described under the AliasWait option.)

The forms of this AutoRebuildAliases option are as follows: ...