IPROUTE(3) IPROUTE(3)
NAME
iproute - Internet route table manager
SYNOPSIS
bind -a #P /net
/net/iproute
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 destination 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 zeroes 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 decreas-
ing 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. Writing 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
`flush'.
For example, to install a gateway address to accept all IP
packets from a machine:
g% echo 'add 0.0.0.0 0.0.0.0 192.20.225.225' > /net/iproute
g% cat /net/iproute
0.0.0.0 & 0.0.0.0 -> 192.20.225.225
SEE ALSO
ip(3), ipconfig(8)
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