diff --git a/admin/halog/halog.c b/admin/halog/halog.c
index 45eec7576..7ff436387 100644
--- a/admin/halog/halog.c
+++ b/admin/halog/halog.c
@@ -207,6 +207,11 @@ void help()
 	       "       -uao, -uto: average times computed on valid ('OK') requests\n"
 	       "       -uba, -ubt: average bytes returned, total bytes returned\n"
 	       " -hdr  output captured header at the given <block>:<field>\n",
+	       " -ac <count> -ad <delay>:\n
+	       "       Report periods corresponding to a grouped accept of <count> requests at\n"
+	       "       the same millisecond after a delay of at least <ad> milliseconds with no\n"
+	       "       incoming accept (used to spot network outages). Output format contains:\n"
+	       "          <accept_date> <date_ms> <delta_ms from previous one> <nb_entries>\n"
 	       (int)SOURCE_FIELD, (int)SOURCE_FIELD
 	       );
 	exit(0);