sendmail, 4th Edition

${if_name_out}

---

The name of the send interface

V8.12 and above

Network interfaces can have one or more addresses associated with each interface, and each address will have a hostname associated with it. For example, on a machine with two interfaces, the one connected to the outside world might have the name host.your.domain , whereas the interface that is connected to the internal network might have the name host.sub.your.domain .

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 hostname associated with the local interface over which the outbound connection was made.

The ${if_name_out} macro is useful with the syslog database-map (syslog) for logging which interface was used to send messages. Note that a $& prefix is necessary when you reference this macro in rules (that is, use $&{if_name_out} , not ${if_name_out} ).

${if_name_out} is transient. If it is defined in the configuration file or in the command line, that definition can be ignored by sendmail .