Update README

diff --git a/README b/README
index f1538f43b242305b879ceabcb6befa8757e8e4df..4afa3984f6b1d8d613245e2c5cfb026e847b3ef9 100644 (file)
--- a/README
+++ b/README
@@ -63,7 +63,7 @@ Environment:
 * SIP_DOMAIN           A space-separated list of SIP domains
 * OPTION_<num> Custom option received as base-16
 * PREFIXES             A space-separated list of prefixes currently assigned
-                               Format: <prefix>/<length>,preferred,valid
+                               Format: <prefix>/<length>,preferred,valid,<excluded-prefix>/<length>
 * ADDRESSES            A space-separated list of addresses currently assigned
                                Format: <address>/<length>,preferred,valid
 * RA_ADDRESSES A space-separated list of addresses from RA-prefixes