+Routes have associated flags which influence operation of the protocols
+when sending to destinations matched by the routes.
+These flags may be set (or sometimes cleared)
+by indicating the following corresponding modifiers:
+.Bd -literal
+-cloning RTF_CLONING - generates a new route on use
+-xresolve RTF_XRESOLVE - emit mesg on use (for external lookup)
+-iface ~RTF_GATEWAY - destination is directly reachable
+-static RTF_STATIC - manually added route
+-nostatic ~RTF_STATIC - pretend route added by kernel or daemon
+-reject RTF_REJECT - emit an ICMP unreachable when matched
+-blackhole RTF_BLACKHOLE - silently discard pkts (during updates)
+-proto1 RTF_PROTO1 - set protocol specific routing flag #1
+-proto2 RTF_PROTO2 - set protocol specific routing flag #2
+-llinfo RTF_LLINFO - validly translates proto addr to link addr
+.Ed
+.Pp