For the string-expansion kind of lookups, the query is given in the first
bracketed argument of the &${lookup ...}$& expansion.
-For the list-argument kind of lookup the quury is given by the remainder of the
+For the list-argument kind of lookup the query is given by the remainder of the
list item after the first semicolon.
.cindex "tainted data" "quoting for lookups"
-If tainted data is used in the query then it should be quuted by
+If tainted data is used in the query then it should be quoted by
using the &*${quote_*&<&'lookup-type'&>&*:*&<&'string'&>&*}*& expansion operator
appropriate for the lookup.
.endlist
.option localhost_number main string&!! unset
.cindex "host" "locally unique number for"
.cindex "message ids" "with multiple hosts"
+.cindex multiple "systems sharing a spool"
+.cindex "multiple hosts" "sharing a spool"
+.cindex "shared spool directory"
+.cindex "spool directory" sharing
.vindex "&$localhost_number$&"
Exim's message ids are normally unique only within the local host. If
-uniqueness among a set of hosts is required, each host must set a different
+uniqueness among a set of hosts is required
+(eg. because they share a spool directory),
+each host must set a different
value for the &%localhost_number%& option. The string is expanded immediately
after reading the configuration file (so that a number can be computed from the
host name, for example) and the result of the expansion must be a number in the
range 0&--16 (or 0&--10 on operating systems with case-insensitive file
systems). This is available in subsequent string expansions via the variable
-&$localhost_number$&. When &%localhost_number is set%&, the final two
+&$localhost_number$&. When &%localhost_number%& is set, the final four
characters of the message id, instead of just being a fractional part of the
time, are computed from the time and the local host number as described in
section &<<SECTmessiden>>&.
follows:
.ilist
-LF not preceded by CR is treated as a line ending.
-.next
CR is treated as a line ending; if it is immediately followed by LF, the LF
is ignored.
.next
.next
If the first header line received in a message ends with CRLF, a subsequent
bare LF in a header line is treated in the same way as a bare CR in a header
-line.
+line and a bare LF in a body line is replaced with a space.
+.next
+If the first header line received in a message does not end with CRLF, a subsequent
+LF not preceded by CR is treated as a line ending.
.endlist
.irow &`deliver_time`& "time taken to attempt delivery"
.irow &`delivery_size`& "add &`S=`&&'nnn'& to => lines"
.irow &`dkim`& * "DKIM verified domain on <= lines"
-.irow &`dkim_verbose`& "separate full DKIM verification result line, per signature"
+.irow &`dkim_verbose`& "separate full DKIM verification result line, per signature; DKIM signing"
.irow &`dnslist_defer`& * "defers of DNS list (aka RBL) lookups"
.irow &`dnssec`& "DNSSEC secured lookups"
.irow &`etrn`& * "ETRN commands"
.cindex log "DKIM verification"
.cindex DKIM "verification logging"
&%dkim_verbose%&: A log entry is written for each attempted DKIM verification.
+.new
+Also, on message delivery lines signing information (domain and selector)
+is added, tagged with DKIM=.
+.wen
.next
.cindex "log" "dnslist defer"
.cindex "DNS list" "logging defer"
.subsection "SRS (Sender Rewriting Scheme)" SECTSRS
.cindex SRS "sender rewriting scheme"
+.cindex VERP "variable envelope return path"
SRS can be used to modify sender addresses when forwarding so that
SPF verification does not object to them.
-It operates by encoding the original envelope sender in a new
+It can also be used to identify a received bounce message as
+likely (or not) having been trigged by a message from the
+local system, and for identifying dead addresses in mailing lists.
+It is one implementation of a VERP (Variable Envelope Return Path) method.
+
+SRS operates by encoding the original envelope sender in a new
sender local part and using a domain run by the forwarding site
as the new domain for the sender. Any DSN message should be returned
to this new sender at the forwarding site, which can extract the