Docs: Add note on lsearch for IPv4-mapped IPv6 addresses

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index d8cf6e73c8bf796ad3b4176d4e747b2dd9e15707..834f210ce19870d2749d98fad94bdf7e111e813a 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -6741,6 +6741,11 @@ lookup types support only literal keys.
 &*Warning 2*&: In a host list, you must always use &(net-iplsearch)& so that
 the implicit key is the host's IP address rather than its name (see section
 &<<SECThoslispatsikey>>&).
+
+.new
+&*Warning 3*&: Do not use an IPv4-mapped IPv6 address for a key; use the
+IPv4.  Such addresses being searched for are converted to IPv4.
+.wen
 .next
 .new
 .cindex lookup json