Update README

diff --git a/README b/README
index a6fa29897a9b3d6bcfbd2f7c441af88f736dc345..16ac904734bdae6e9ce166023e2be65543beb529 100644 (file)
--- a/README
+++ b/README
@@ -68,7 +68,7 @@ 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,<excluded-prefix>/<length>
+                               Format: <prefix>/<length>,preferred,valid[,excluded=<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