Beginning with V8.12 sendmail, it is possible to fill a class macro with values from an ldap database map. The general form looks like this:

F{classname}@ldap:switches 

The switches are ldap database map-type switches that might look something like this:

-k (&(objectClass=someclass)) -v  classvalue  

An alternative form of ldap database map-type declaration uses default switches:

F{classname}@LDAP

Here, the literal @LDAP tells sendmail to use default switches that look like the following (where the line has been split to fit the page):

-k (&(objectClass=sendmailMTAClass)(sendmailMTAClassName=ClassName)
   (|(sendmailMTACluster=${sendmailMTACluster})(sendmailMTAHost=$j)))
   -v sendmailMTAClassValue

Note that the default sendmailMTACluster is based on the value in the ${sendmailMTACluster} macro.

If you plan to use the @LDAP default, you will need to define the ${sendmailMTACluster} macro in your mc configuration file, as for example:

define(`confLDAP_CLUSTER', `clustername')

${sendmailMTACluster} is intended for use only in the default @LDAP setting.