fix typo

diff --git a/doc/arm/Bv9ARM-book.xml b/doc/arm/Bv9ARM-book.xml
index ed144879d277e46517776127c31b87839824797c..5a1fcb9b0cb04f872eb3f0ce5b0293cf57d7fec5 100644 (file)
--- a/doc/arm/Bv9ARM-book.xml
+++ b/doc/arm/Bv9ARM-book.xml
@@ -10017,7 +10017,7 @@ example.com                 CNAME   rpz-tcp-only.
            Requests for any and all undefined subdomains of a given
            valid domain result in NXDOMAIN errors, and are identical
            regardless of query type.
-           They are limited by <command>nxdomain-per-second</command>
+           They are limited by <command>nxdomains-per-second</command>
            (default base <command>responses-per-second</command>).
            This controls some attacks using random names, but
            can be relaxed or turned off (set to 0)