The route Command

If an end station has multiple interfaces, it can be useful to know which of these interfaces is
being used for particular destinations. In theses cases, for both Windows NT/2000/XP stations
and Unix stations, you can use the route command. The following are the options and the syntax
for displaying the routing table for Windows NT/2000/XP:
C:\>route /?
Manipulates network routing tables.
ROUTE [-f] [-p] [command [destination] [MASK netmask] [gateway]
[METRIC metric] [IF interface]
-f Clears the routing tables of all gateway entries. If this is
used in conjunction with one of the commands, the tables are
cleared prior to running the command.
-p When used with the ADD command, makes a route persistent across
boots of the system. By default, routes are not preserved when
the system is restarted. Ignored for all other commands, which
always affect the appropriate persistent routes. This option
is not supported in Windows 95.
command One of these:
PRINT Prints a route
ADD Adds a route
DELETE Deletes a route
CHANGE Modifies an existing route
destination Specifies the host.
MASK Specifies that the next parameter is the 'netmask' value.
netmask Specifies a subnet mask value for this route entry. If not
specified, it defaults to 255.255.255.255.
gateway Specifies gateway.
interface The interface number for the specified route.
METRIC Specifies the metric, ie. cost for the destination.
All symbolic names used for destination are looked up in the network Database
file NETWORKS. The symbolic names for gateway are looked up in the host name
database file HOSTS.
If the command is PRINT or DELETE. Destination or gateway can be a wildcard,
(wildcard is specified as a star '*'), or the gateway argument may be omitted.
If Dest contains a * or ?, it is treated as a shell pattern, and only matching
destination routes are printed. The '*' matches any string, and '?' matches
any one char. Examples: 157.*.1, 157.*, 127.*, *224*.
Diagnostic Notes:
Invalid MASK generates an error, that is when (DEST & MASK) !=
DEST.
Example> route ADD 157.0.0.0 MASK 155.0.0.0 157.55.80.1 IF 1
The route addition failed: The specified mask parameter is
invalid.
(Destination & Mask) != Destination.
Examples:
> route PRINT
> route ADD 157.0.0.0 MASK 255.0.0.0 157.55.80.1 METRIC 3 IF 2
destination^ ^mask ^gateway metric^ ^
Interface^
If IF is not given, it tries to find the best interface for a
given gateway.
> route PRINT
> route PRINT 157* .... Only prints those matching 157*
> route CHANGE 157.0.0.0 MASK 255.0.0.0 157.55.80.5 METRIC 2 IF 2
CHANGE is used to modify gateway and/or metric only.
> route PRINT
> route DELETE 157.0.0.0
> route PRINT
C:\>route print
=======================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x2 ... 00 04 f2 cd 65 1f...... NVIDIA nForce MCP Networking Adapter -
➥Packet Scheduler Miniport
=======================================================================
=======================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 10.12.1.1 10.12.1.11 20
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
10.12.1.0 255.255.255.0 10.12.1.11 10.12.1.11 20
10.12.1.11 255.255.255.255 127.0.0.1 127.0.0.1 20
10.12.1.255 255.255.255.255 10.12.1.11 10.12.1.11 20
224.0.0.0 240.0.0.0 10.12.1.11 10.12.1.11 20
255.255.255.255 255.255.255.255 10.12.1.11 10.12.1.11 1
Default Gateway: 10.12.1.1
=======================================================================
Persistent Routes:
None
For the Unix side of things, the options and sample printout are as follows:
unix1% route
usage: route [ -fnqv ] cmd [[ - ] args ]
unix1% route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.12.1.0 0.0.0.0 255.255.255.0 U 0 0 0 hme0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
0.0.0.0 10.12.1.1 0.0.0.0 UG 0 0 0 hme0

In addition to printing out the routing table, the route command can also be used to add or
delete static routes if they are needed.