The value is a text representation of an
integer value. If ${tls_version} has a value, the value in ${cipher_bits} is included as part
of the text in the Received: header:
(version=${tls_version} cipher=${cipher} bits=${cipher_bits} verify=${verify})
If ${tls_version} lacks a value, the preceding text is not included.
${cipher_bits} is transient. If it is defined in the configuration file or in the command line,
that definition is ignored by sendmail. Note that a $& prefix is necessary when you reference
this macro in rules (that is, use $&{cipher_bits}, not ${cipher_bits}).
21.9.18 ${client_addr}
The connecting host??™s IP address V8.8 and later
The ${client_addr} macro is assigned its value when a host connects to the running
daemon. The value assigned is the IP address of that connecting host and is the same as the
IP address stored in the $_ macro, but without the surrounding square brackets and other
non-IP information.
The ${client_addr} macro can be useful in the Local_check_rcpt (?§7.1.3 on page 257) and
Local_check_mail (?§7.1.2 on page 255) rule sets. It can, for example, be used to detect
whether an external host is trying to send external mail through your outgoing firewall
machine:
This is the Title of the Book, eMatter Edition
Copyright ?© 2007 O??™Reilly & Associates, Inc. All rights reserved.
21.9 Alphabetized sendmail Macros | 811
LOCAL_CONFIG
D{ourdomain}123.
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