stop-gap: doc glibc 2.31 RES_TRUSTAD/trust-ad

[exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 0f46896e97172469ba7415552a04bab5dcc02cec..c54437181b2bc1bfd83c2109fd4bf07f54b88550 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -8120,7 +8120,7 @@ daemon as in the other SQL databases.
 
 .new
 .oindex &%sqlite_dbfile%&
 
 .new
 .oindex &%sqlite_dbfile%&

-The preferred way of specifying the file is by using the 
+The preferred way of specifying the file is by using the

 &%sqlite_dbfile%& option, set to
 an absolute path.
 .wen
 &%sqlite_dbfile%& option, set to
 an absolute path.
 .wen


@@ -13290,6 +13290,18 @@ library, by setting:
 dns_dnssec_ok = 1
 .endd
 
 dns_dnssec_ok = 1
 .endd
 

+.new
+In addition, on Linux with glibc 2.31 or newer the resolver library will
+default to stripping out a successful validation status.
+This will break a previously working Exim installation.
+Provided that you do trust the resolver (ie, is on localhost) you can tell
+glibc to pass through any successful validation with a new option in
+&_/etc/resolv.conf_&:
+.code
+options trust-ad
+.endd
+.wen
+

 Exim does not perform DNSSEC validation itself, instead leaving that to a
 validating resolver (e.g. unbound, or bind with suitable configuration).
 
 Exim does not perform DNSSEC validation itself, instead leaving that to a
 validating resolver (e.g. unbound, or bind with suitable configuration).
 


@@ -15418,6 +15430,18 @@ default. A value of 0 coerces DNSSEC off, a value of 1 coerces DNSSEC on.
 
 If the resolver library does not support DNSSEC then this option has no effect.
 
 
 If the resolver library does not support DNSSEC then this option has no effect.
 

+.new
+On Linux with glibc 2.31 or newer this is insufficient, the resolver library
+will default to stripping out a successful validation status.
+This will break a previously working Exim installation.
+Provided that you do trust the resolver (ie, is on localhost) you can tell
+glibc to pass through any successful validation with a new option in
+&_/etc/resolv.conf_&:
+.code
+options trust-ad
+.endd
+.wen
+

 
 .option dns_ipv4_lookup main "domain list&!!" unset
 .cindex "IPv6" "DNS lookup for AAAA records"
 
 .option dns_ipv4_lookup main "domain list&!!" unset
 .cindex "IPv6" "DNS lookup for AAAA records"