Thus, in the default case, as long as at least one of the DNS lookups
yields some data, the lookup succeeds.
+.new
+.cindex "DNSSEC" "dns lookup"
Use of &(DNSSEC)& is controlled by a dnssec modifier.
The possible keywords are
&"dnssec_strict"&, &"dnssec_lax"&, and &"dnssec_never"&.
With &"strict"& a response from the DNS resolver that
is not labelled as authenticated data
is treated as equivalent to a temporary DNS error.
-The default is &"never".
+The default is &"never"&.
+
+See also the &$lookup_dnssec_authenticated$& variable.
+.wen
&`USER `& set the DN, for authenticating the LDAP bind
&`PASS `& set the password, likewise
&`REFERRALS `& set the referrals parameter
+.new
&`SERVERS `& set alternate server list for this query only
+.wen
&`SIZE `& set the limit for the number of entries returned
&`TIME `& set the maximum waiting time for a query
.endd
The TIME parameter (also a number of seconds) is passed to the server to
set a server-side limit on the time taken to complete a search.
+.new
The SERVERS parameter allows you to specify an alternate list of ldap servers
to use for an individual lookup. The global ldap_servers option provides a
default list of ldap servers, and a single lookup can specify a single ldap
different than the default list (maybe different order, maybe a completely
different set of servers), the SERVERS parameter allows you to specify this
alternate list.
-
+.wen
Here is an example of an LDAP query in an Exim lookup that uses some of these
values. This is a single line, folded to fit on the page:
the space value is -1. See also the &%check_log_space%& option.
+.new
+.vitem &$lookup_dnssec_authenticated$&
+.vindex "&$lookup_dnssec_authenticated$&"
+This variable is set after a DNS lookup done by
+either a dnslookup router or a dnsdb lookup expansion.
+It will be empty if &(DNSSEC)& was not requested,
+&"no"& if the result was not labelled as authenticated data
+and &"yes"& if it was.
+.wen
+
.vitem &$mailstore_basename$&
.vindex "&$mailstore_basename$&"
This variable is set only when doing deliveries in &"mailstore"& format in the
+.new
.option dnssec_request_domains dnslookup "domain list&!!" unset
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
the dnssec request bit set.
This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+See also the &$lookup_dnssec_authenticated$& variable.
+.wen
+
+.new
.option dnssec_require_domains dnslookup "domain list&!!" unset
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
the dnssec request bit set. Any returns not having the Authenticated Data bit
(AD bit) set wil be ignored and logged as a host-lookup failure.
This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+.wen