CompTIA Certifications

CompTIA Network+ 2009 Domain 5: Network Tools

Route Networking Utility

The route networking utility allows you to change network routing tables. A routing table is a data structure, similar to a database, which lists the routes to particular network destinations. The routing table is constructed automatically using network protocols to discover the topology of the network the machine is located on. You can create a static route manually to override the automatic routes discovered.


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
 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 MASK IF 1
 The route addition failed: The specified mask parameter is invalid.
 (Destination & Mask) != Destination.


 > route PRINT
 > route ADD MASK METRIC 3 IF 2
 destination^      ^mask      ^gateway     metric^    ^
 If IF is not given, it tries to find the best interface for a given
 > route PRINT
 > route PRINT 157*          .... Only prints those matching 157*

Route can be used when you have a routing problem on the network. It is a dangerous tool if you do not understand what you’re doing, you could easily route traffic someplace you should not and prevent networking from functioning properly on a given machine. The route print command provides some routing troubleshooting information that you could use if the machine is not reaching a particular destination.