Windows running SMTPL.EXE 1.0w or later for inbound mail
If SMTPL spam control is enabled, contains the space-separated list of target hostnames to check. Normally this is handled by setting the value to %MYDOMAIN%.
Windows: SMTP_SPAM_CHECK=EXAMPLE.COM LISTSERV.EXAMPLE.COM
For full information on this feature, please see Section 5.1, SMTPL-Level Spam Control for Windows, in the Advanced Topics Manual for LISTSERV.
Not set; SMTPL spam control disabled.