Trend Micro Email
Security allows you to specify an IP address
or a range of addresses within a sender domain identified by the message
header address to allow email messages only from those addresses. Sender IP Match is a
way that readily enables you to simultaneously allow all inbound email traffic from
a particular
domain while equally preventing spoofing by manually defining the allowed IP ranges.
If an email message passes the Sender IP Match check, Trend Micro Email
Security skips its own SPF check as well as the SPF check of
DMARC authentication for this message.