x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
IFROUTE(5) Network configuration IFROUTE(5)
NAME
ifroute - configure the interface static routing tables
SYNOPSIS
/etc/sysconfig/network/ifroute-<interface>
/etc/sysconfig/network/routes
DESCRIPTION
The /etc/sysconfig/network/ifroute-<interface> and the /etc/syscon-
fig/network/routes file are parsed together with the /etc/syscon-
fig/network/ifcfg-<interface> file to set up static routes for a par-
ticular interface.
The /etc/sysconfig/network/ifroute-<interface> file contains routes for
the particular interface while the /etc/sysconfig/network/routes can
contain routes for all interfaces.
The currently assigned routes can be seen by issuing:
/sbin/ip -4 route show ; /sbin/ip -6 route show
which will give the current (main) routing tables.
Syntax
Both files use the same syntax. The only difference is the interpreta-
tion the interface field in the 4th column.
Lines beginning with # and blank lines are ignored. There are 5 columns
with special meaning. Write a dash "-" if you want to omit an entry
for a field. If all following fields in the line are empty too, you can
even omit the dash.
The columns are: Destination Gateway Netmask Interface Options
The 1st, Destination column gives the destination / prefix, written as
the IP-address of a host or as a network in a prefix-length (CIDR nota-
tion), e.g. 10.10.0.0/16 for IPv4 or fc00::/7 for IPv6 routes. The
heading default indicates that the route is the default gateway in the
same address family (ipv4 or ipv6) as the gateway. For device routes
without a gateway use explicit 0.0.0.0/0 or ::/0 destinations.
The 2nd, Gateway column defines the gateway. Write here the regular IP-
address of a host which routes the packets to a remote host or remote
network. You can omit this information for rejecting or device routes
using a dash '-'.
The 3rd, Netmask column is deprecated and gives the IPv4 netmask of the
destination. For IPv6 routes, the default route or if you were using a
prefix-length (CIDR notation) in the 1st destination column, you can
omit it using a dash '-'.
The 4th, Interface column contains the name of the interface (lo, eth0,
eth1, ib0, ...).
If you leave this field empty (using a dash '-'), the result depends on
the file you are using.
In /etc/sysconfig/network/routes the field is interpreted as no inter-
face information available and the gateway is examined if it belongs to
the same network as a IPADDR in all (currently parsed) ifcfg-<inter-
face> files. The first IP address match is used, so if you have multi-
ple interfaces, such a route may match multiple IP addresses and cause
unintended behavior.
In the latter case you may want to use the /etc/sysconfig/net-
work/ifroute-<interface> instead. Here an empty interface field is
replaced with the interface name that is currently being activated,
that is the interface in the file name.
The 5th, Options column can be used to specify further options for the
route like preference (metric), mtu or the type of a route:
unicast
The route entry describes real paths to the destinations covered
by the route prefix.
local The destinations are assigned to this host. The packets are
looped back and delivered locally.
broadcast
The destinations are broadcast addresses. The packets are sent
as link broadcasts.
multicast
A special type used for multicast routing. It is not present in
normal routing tables.
throw A special control route used together with policy rules. If such
a route is selected, lookup in this table is terminated pretend-
ing that no route was found. Without policy routing it is equiv-
alent to the absence of the route in the routing table. The
packets are dropped and the ICMP message net unreachable is gen-
erated. The local senders get an ENETUNREACH error.
unreachable
These destinations are unreachable. Packets are discarded and
and the ICMP message host unreachable is generated. The local
senders get an EHOSTUNREACH error.
prohibit
These destinations are unreachable. Packets are discarded and
the ICMP message communication administratively prohibited is
generated. The local senders get an EACCES error.
blackhole
These destinations are unreachable. Packets are discarded
silently. The local senders get an EINVAL error.
nat A special NAT route, not supported any longer since Linux 2.6.
All options (except of to, via and dev used in columns 1-4) of the
ip route add command shall be supported.
Columns which are not needed should contain a dash sign ( - ) to ensure
that the parser correctly interprets the command.
EXAMPLES
An example with common network interfaces and some static routes:
# --- IPv4 routes in CIDR prefix notation:
# Destination [Gateway] - Interface
#
127.0.0.0/8 - - lo
204.127.235.0/24 - - eth0
default 204.127.235.41 - eth0
207.68.156.51/32 207.68.145.45 - eth1
192.168.0.0/16 207.68.156.51 - eth1
# --- IPv4 routes in deprecared netmask notation:
# Destination [Dummy/Gateway] Netmask Interface
#
127.0.0.0 0.0.0.0 255.255.255.0 lo
204.127.235.0 0.0.0.0 255.255.255.0 eth0
default 204.127.235.41 0.0.0.0 eth0
207.68.156.51 207.68.145.45 255.255.255.255 eth1
192.168.0.0 207.68.156.51 255.255.0.0 eth1
# --- IPv6 routes are always using CIDR notation:
# Destination [Gateway] - Interface
#
2001:DB8:100::/64 - - eth0
2001:DB8:100::/32 fe80::216:3eff:fe6d:c042 - eth0
Note:
Routes to directly connected network are created automatically (Linux
kernel 2.4 and later) as soon as the IP address is assigned to the
interface.
For example, when the eth0 interface IP addresses are 204.127.235.42/24
and 2001:DB8:100::42/64, the following routes are created automati-
cally:
204.127.235.0/24 - - eth0
2001:DB8:100::/64 - - eth0
fe80::/64 - - eth0
and should be omitted.
FILES
/etc/sysconfig/network/ifroute-<interface>
/etc/sysconfig/network/routes
AUTHOR
Michal Svec
Christian Zoz
Mads Martin Joergensen
Marius Tomaschewski
Thanks to Werner Fink for the old route.conf(5). Parts of the ip ref-
erence by Alexey Kuznetsov and ip-route man page by Michail Litvak and
others were also used.
SEE ALSO
ifcfg(5), ip-route(8)
sysconfig May 2014 IFROUTE(5)
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