Mail addressed to a local user that includes the name of the local host as part of the address (i.e., user@local.host) is delivered locally. From V8.1 to V8.6 sendmail, if the address has a host part, lookups in the User Database (userdb) and the additional processing of the localaddr rule set 5 (Section 19.6) are skipped. Under V8.6, addresses with just the user part are always processed by the User Database and the localaddr rule set 5.

The V8.6 notsticky feature changes this logic. If this feature is chosen, all users are looked up in the User Database, and the additional processing done by the localaddr rule set 5 is skipped.

Beginning with V8.7, the default is as if notsticky were used, and thus the stickyhost feature can be used to restore the previous default.