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IPROUTE(3)                 Library Functions Manual                 IPROUTE(3)



NAME
       iproute - Internet route table manager

SYNOPSIS
       bind -a #P /net

       /net/iproute
       /net/ipifc

DESCRIPTION
       The  iproute  device allows the specification of routes for families of
       IP addresses.  It maintains a  kernel-resident  routing  table  for  IP
       addresses  used  by TCP, IL and UDP.  Each route consists of a destina-
       tion IP address, an IP mask, and an IP gateway address.   Every  packet
       sent  by the system is routed according to the route table.  An address
       matches the route table  entry  when  a  packet's  destination  address
       matches  the  table destination address under the mask. When a match is
       found, the packet is sent to the gateway IP address.  If  there  is  no
       match,  the  packet  is sent with the original destination address.  If
       there are several matches, the one whose mask has  the  fewest  leading
       zeros  is  chosen.   (Because  of the definition of IP masks, this mask
       preserves the largest portion of the address and is therefore the  most
       specific.)   This  is forced by storing the routes in decreasing number
       of ones order and returning the first match.  The default  gateway  has
       no ones in the mask and is thus the last matched.

       Reading iproute reports the current routes entered in the table.  Writ-
       ing control messages to iproute edits the  table.   Route  entries  are
       made by writing a string of format

              add ipdest mask ipgateway

       Entries are deleted by writing a string of format

              delete ipdest mask

       The whole table can be cleared by writing the string

       For example, to install a gateway address to accept all IP packets from
       a machine:

              % echo 'add 0.0.0.0 0.0.0.0 131.107.1.5' > /net/iproute
              % cat /net/iproute
              0.0.0.0 & 0.0.0.0 -> 131.107.1.5

       Reading ipifc reports the current IP interfaces being  used,  one  line
       per interface, showing the device, the maximum transfer unit, the local
       address, the network mask, and the network address.

SOURCE
       /sys/src/9/port/deviproute.c

SEE ALSO
       ip(3), ipconfig(8)



                                                                    IPROUTE(3)