Added Tony's defer_foo patch to dnsdb lookups.

2 files changed, 19 insertions, 6 deletions

diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 6774dad4a..a12145aeb 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.46 2004/12/20 14:57:05 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/ChangeLog,v 1.47 2004/12/20 15:24:27 ph10 Exp $
 
 Change log file for Exim from version 4.21
 -------------------------------------------
@@ -157,7 +157,8 @@ Exim version 4.50
         just the host names, not the priorities.
 
     (3) It is now possible to give a list of domains (or IP addresses) to be
-        looked up.
+        looked up. The behaviour when one of the lookups defers can be
+        controlled by a keyword.
 
     (4) It is now possible to specify the separator character for use when
         multiple records are returned.
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index 16c9c4653..3109ea96f 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -1,4 +1,4 @@
-$Cambridge: exim/doc/doc-txt/NewStuff,v 1.20 2004/12/17 14:52:44 ph10 Exp $
+$Cambridge: exim/doc/doc-txt/NewStuff,v 1.21 2004/12/20 15:24:27 ph10 Exp $
 
 New Features in Exim
 --------------------
@@ -152,9 +152,21 @@ Version 4.50
     single item are handled.
 
     The dnsdb lookup fails only if all the DNS lookups fail. If there is a
-    temporary DNS error for any of them, the remaining lookups are still done,
-    and only if none of them succeed does the dnsdb lookup defer. As long as at
-    least one of the DNS lookups yields some data, the dnsdb lookup succeeds.
+    temporary DNS error for any of them, the behaviour is controlled by
+    an optional keyword followed by a comma that may appear before the record
+    type. The possible keywords are "defer_strict", "defer_never", and
+    "defer_lax". With "strict" behaviour, any temporary DNS error causes the
+    whole lookup to defer. With "never" behaviour, a temporary DNS error is
+    ignored, and the behaviour is as if the DNS lookup failed to find anything.
+    With "lax" behaviour, all the queries are attempted, but a temporary DNS
+    error causes the whole lookup to defer only if none of the other lookups
+    succeed. The default is "lax", so the following lookups are equivalent:
+
+      ${lookup dnsdb{defer_lax,a=one.host.com:two.host.com}}
+      ${lookup dnsdb{a=one.host.com:two.host.com}}
+
+    Thus, in the default case, as long as at least one of the DNS lookups
+    yields some data, the dnsdb lookup succeeds.
 
 15. It is now possible to specify the character to be used as a separator when
     a dnsdb lookup returns data from more than one DNS record. The default is a