.IR mtu ]
.RB [ -o
.IR dhcp-opt ]
+.RB [ -f
+.IR dbfile ]
.RB [ -x
.IR netmtpt ]
[
which removes any existing ARP table entry for one of our IPv6 addresses
before adding new ones.
.TP
+.B f
+use the ndb database file
+.I dbfile .
+.TP
.B x
use the IP stack mounted at
.I netmtpt