ROUTE(8c,C) AIX TCP/IP User's Guide ROUTE(8c,C) ------------------------------------------------------------------------------- route PURPOSE Manually manipulates the routing tables. SYNTAX +--------+ +-- add ---+ +----------+ route ---| +----+ |---| |---| one of |-- destination -... +-| -f |-+ +- delete -+ | +------+ | ^| -n || +-| net |-+ |+----+| | host | +------+ +------+ ...- gateway -- metric ---| DESCRIPTION The route command is used to manually manipulate the network routing tables. It normally is not needed, as the system routing table management daemon, routed, tends to this task. The route command accepts two commands: add, to add a route, and delete, to delete a route. In addition the route command accepts the following parameters: destination Is the destination host or network. gateway Is the next-hop gateway to which packets should be addressed. 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 interface to be used for transmission. Routes to a particular host are distinguished 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 Processed October 29, 1990 ROUTE(8c,C) 1 ROUTE(8c,C) AIX TCP/IP User's Guide ROUTE(8c,C) 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. 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. If this lookup fails, getnetbyname is then used to interpret the name as that of a network. The optional keyword default may be substituted for the destination parameter. This causes the gateway specified as the next parameter to be treated as the default exit point for the network. This "default gateway" will be used for any packet with an unrecognized address. This provides a place for packets to be sent when the host handling the packet can not find the Internet address in its own route table. A "default" gateway" is very useful; it is often specified when there are hosts in the network that are not running routed. The route command uses a raw socket and the SIOCADDRT and SIOCDELRT ioctl's to do its work. As such, only the superuser may modify the routing tables. FLAGS The route command options are: -f Flushes 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. -n Prevents attempts to print host and network names symbolically when reporting actions. EXAMPLES # /etc/route add newnet thishost 3 # /etc/route delete newnet thishost MESSAGES add [ host | network ] destination gateway Explanation: 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 ] destination gateway Explanation: As above, but when deleting an entry. Processed October 29, 1990 ROUTE(8c,C) 2 ROUTE(8c,C) AIX TCP/IP User's Guide ROUTE(8c,C) Flushing routing tables: destination gateway Explanation: When the -f flag is specified, each routing table entry deleted is indicated with a message of this form. network is unreachable Explanation: 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 Explanation: A delete operation was attempted for an entry which wasn't present in the tables. routing table overflow Explanation: An add operation was attempted, but the system was low on resources and was unable to allocate memory to create the new entry. RELATED INFORMATION In this book: "routed" Processed October 29, 1990 ROUTE(8c,C) 3