4.3BSD - /usr/man/cat8/route.0

ROUTE(8C)                                                            ROUTE(8C)


NAME
       route - manually manipulate the routing tables

SYNOPSIS
       /etc/route [ -f ] [ -n ] [ command args ]

DESCRIPTION
       Route  is  a  program  used  to manually manipulate the network routing
       tables.  It normally is not needed, as the system routing table manage‐
       ment daemon, routed(8C), should tend to this task.

       Route  accepts two commands: add, to add a route, and delete, to delete
       a route.

       All commands have the following syntax:

         /etc/route command [ net | host ] destination gateway [ metric ]

       where destination is the destination host or network,  gateway  is  the
       next-hop  gateway to which packets should be addressed, and metric is a
       count indicating the number of hops to the destination.  The metric  is
       required  for  add commands; it must be zero if the destination is on a
       directly-attached network, and nonzero if the  route  utilizes  one  or
       more  gateways.   If adding a route with metric 0, the gateway given is
       the address of this host on the common network, indicating  the  inter‐
       face to be used for transmission.  Routes to a particular host are dis‐
       tinguished from those to a network by interpreting the Internet address
       associated  with destination.  The optional keywords net and host force
       the destination to be interpreted as a network or a host, respectively.
       Otherwise,   if  the  destination  has  a  ‘‘local  address  part’’  of
       INADDR_ANY, or if the destination is the symbolic name  of  a  network,
       then the route is assumed to be to a network; otherwise, it is presumed
       to be a route to a host.  If the route is to  a  destination  connected
       via a gateway, the metric should be greater than 0.  All symbolic names
       specified for a destination or gateway are looked up first  as  a  host
       name  using  gethostbyname(3N).  If this lookup fails, getnetbyname(3N)
       is then used to interpret the name as that of a network.

       Route uses a raw socket and the SIOCADDRT and SIOCDELRT ioctl’s  to  do
       its  work.  As such, only the super-user may modify the routing tables.

       If the -f option is specified, route will ‘‘flush’’ the routing  tables
       of all gateway entries.  If this is used in conjunction with one of the
       commands described above, the tables are flushed prior to the command’s
       application.

       The -n option prevents attempts to print host and network names symbol‐
       ically when reporting actions.

DIAGNOSTICS
       ‘‘add [ host | network ] %s: gateway %s flags %x’’
       The specified route is being added to the tables.  The  values  printed
       are  from  the  routing table entry supplied in the ioctl call.  If the
       gateway address used was not the primary address of  the  gateway  (the
       first  one  returned  by gethostbyname), the gateway address is printed
       numerically as well as symbolically.

       ‘‘delete [ host | network ] %s: gateway %s flags %x’’
       As above, but when deleting an entry.

       ‘‘%s %s done’’
       When the -f flag is specified, each  routing  table  entry  deleted  is
       indicated with a message of this form.

       ‘‘Network is unreachable’’
       An  attempt to add a route failed because the gateway listed was not on
       a directly-connected network.  The next-hop gateway must be given.

       ‘‘not in table’’
       A delete operation was attempted for an entry which wasn’t  present  in
       the tables.

       ‘‘routing table overflow’’
       An add operation was attempted, but the system was low on resources and
       was unable to allocate memory to create the new entry.

SEE ALSO
       intro(4N), routed(8C), XNSrouted(8C)


4.2 Berkeley Distribution        May 24, 1986                        ROUTE(8C)