x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
IFSYSCTL(5) IFSYSCTL(5)
NAME
ifsysctl[-<interface name>] - per network interface sysctl settings
SYNOPSIS
system sysctl files:
/boot/sysctl.conf-<kernelversion>
/run/sysctl.d/*.conf
/etc/sysctl.d/*.conf
/usr/local/lib/sysctl.d/*.conf
/usr/lib/sysctl.d/*.conf
/lib/sysctl.d/*.conf
/etc/sysctl.conf
wicked ifsysctl files (deprecated):
/etc/sysconfig/network/ifsysctl
/etc/sysconfig/network/ifsysctl-`<interface>`
DESCRIPTION
The settings from the system sysctl files are applied by sys-
temd-sysctl.service at boot as well as the per-interface settings by
udev rules when the interface appears in the system.
The following configuration sets are supported by the kernel:
o all: common runtime behavior policy for all currently existing inter-
faces.
o default: template used to initialize the interface sysctls, when a
new interface is created
o <interface>: interface specific behavior
Wicked is never applying the all or default sysctl settings to the ker-
nel, but considers them and the <interface> sysctl settings (with high-
est priority), when parsing the ifcfg-<interface> files.
The ifcfg variables and the sysctl settings are used as protocol set-
tings in the effective wicked xml configuration, visible in the 'wicked
show-config' output.
The wicked xml interface configuration is sent by 'wicked ifup' and
'wicked ifreload' to the wickedd* backends, which are applying the
sysctl settings from the xml configuration to the kernel on configura-
tion changes, hotplug events and wickedd service restart (e.g. on
wicked package update).
Interface sysctl settings initialized by the kernel to -1 (not applica-
ble for this interface) are not overwritten by wickedd.
SYSCTL PITFALLS
o Each sysctl has its own specific processing in the kernel. For de-
tails, please read the kernel documentation https://www.ker-
nel.org/doc/Documentation/networking/ip-sysctl.rst.
o Applying changes to the all sysctl set (e.g. using 'sysctl -w ...')
is propagated (in many cases) by the kernel in time of execution also
to default and the interface specific sysctl of all existing inter-
faces.
o Enabling forwarding changes the system role from host to router.
This has impact on several other sysctl's like the IPv6 RA processing
(see accept_ra) and IPv6 autoconfiguration:
o there is no automatic IPv6 default route configuration
o there is no automatic IPv6 route to the prefix network
o there are no IPv6 addresses applied by SLAAC and DHCPv6
o the nameservers sent in the RA are not applied to resolv.conf
The accept_ra = 2 sysctl (on affected uplink interface) enables RA
processing on a router.
o Wicked is considering system sysctl configuration and may revert tem-
porary runtime changes ('sysctl -w ...'), e.g. applied by another
programs (see DESCRIPTION).
SYSCTL VARIABLES
IPv4
net.ipv4.conf.{all,default,interface}.forwarding
Enable IP forwarding changing the system role between host and
router.
net.ipv4.conf.{all,default,interface}.arp_notify
Define mode for notification of address and device changes.
This setting is also set by SEND_GRATUITOUS_ARP, which has
precedence over sysctl (see man ifcfg).
IPv6:
net.ipv6.conf.{all,default,interface}.disable_ipv6
Enable/Disable IPv6 operation.
net.ipv6.conf.{all,default,interface}.forwarding
Enable IPv6 forwarding changing the system role between host and
router. Note: Several other sysctl's, dhcp6, auto6 and routing
have functional dependency to the forwarding sysctl (see SYSCTL
PITFALLS).
net.ipv6.conf.{all,default,interface}.accept_ra
Accept Router Advertisements and perform IPv6 autoconfiguration
of the interface if accept_ra > forwarding.
net.ipv6.conf.{all,default,interface}.autoconf
Autoconfigure addresses using Prefix Information in Router Ad-
vertisements.
net.ipv6.conf.{all,default,interface}.use_tempaddr
Preference for Privacy Extensions (RFC3041), ignored for loop-
back interface.
net.ipv6.conf.{all,default,interface}.accept_dad
Whether to accept DAD (Duplicate Address Detection), ignored for
loopback interface.
net.ipv6.conf.{interface}.accept_redirects
Accept Redirects. Wicked considers only interface specific set-
tings.
net.ipv6.conf.{all,default,interface}.addr_gen_mode
Defines how link-local and managed autoconf addresses are gener-
ated.
net.ipv6.conf.{all,default,interface}.stable_secret
This IPv6 address will be used as a secret to generate IPv6 ad-
dresses for link-local and autoconfigured addresses.
SYNTAX
The sysctl configuration supports two separator characters for sysctl
keywords: a "." in default format and a "/" in the alternate format.
Therefore, the syntax is the same as is found in the /etc/sysctl.conf
file.
EXAMPLES
Settings for "eth0" and "eth0.1" interfaces
# using "." as separator:
net.ipv6.conf.eth0.use_tempaddr = 2
net.ipv6.conf.eth0/1.use_tempaddr = 2
# using "/" as separator:
net/ipv6/conf/eth0/use_tempaddr = 2
net/ipv6/conf/eth0.1/use_tempaddr = 2
COPYRIGHT
Copyright (C) 2024 SUSE LLC
BUGS
Please report bugs as described at <https://bugs.opensuse.org>
SEE ALSO
ifup (8), ifcfg (5), sysctl (8), systemd-sysctl (8)
AUTHORS
Marius Tomaschewski, Clemens Famulla-Conrad.
Wicked User Manual October 2024 IFSYSCTL(5)
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