Short Description: If set allows mail relays to known domains only.
SMTPMTA_Allow_Known_Domains=1 allows mail relays to known domains only. Mail for a recipient is rejected if the connecting host resides in an unknown domain, and the recipient also resides in an unknown domain. Mail for a recipient is only accepted if either the connecting host or the recipient resides in a known domain. (Note that SMTP_Allow_Known_Domains should not be used with SMTPMTA_Reject_Relays.)
See SPR# DMNL3TCLHM, ALAE3ZANQL & MBED3YTRRY for more information on this keyword.
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