${if_family_out}
The network family of the send interface V8.12 and later
The sendmail program can send
SMTP email over one or more network interfaces,
where each interface can have one or more addresses
associated with it. When
sendmail sends a network
email message, it begins by connecting to a host on
the network. Once that connection has been made
(once the other site accepts the connection),
sendmail records in the
${if_addr_out}
macro the address associated with the interface over
which it made that outbound connection. It then
records the family to which that address belongs in
the ${if_family_out}
macro. The family is a
text representation of an integer value that
represents the family, as defined in
sys/socket.h. A value of 2,
for example, could represent the AF_INET
family.
${if_family_out}
is
available for use in rule sets, and can be useful
for rejecting spam or restricting connections to
particular addresses. Note that a $&
prefix is
necessary when you reference this macro in rules
(that is, use $&{if_family_out}
, not ${if_family_out}
).
${if_family_out}
is
transient. If it is defined in the configuration
file or in the command line, that definition can be
ignored by sendmail.
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