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✏️ Editing: sysconfig.txt

=======================

Generic options:

/etc/sysconfig/*

CGROUP_DAEMON=
     List of control groups that the daemon will be run in. For example,
     CGROUP_DAEMON="cpu:daemons cpuacct:/" will run it in the daemons
     group for the CPU controller, and the '/' group for the CPU accounting
     controller.

/etc/sysconfig/authconfig

used by authconfig to store information about the system's user
  information and authentication setup; changes made to this file
  have no effect until the next time authconfig is run

USEHESIOD=no
      Whether or not the hesiod naming service is in use.  If not set,
      authconfig examines the passwd setting in /etc/nsswitch.conf.
    USELDAP=no
      Whether or not LDAP is used as a naming service.  If not set,
      authconfig examines the passwd setting in /etc/nsswitch.conf.
    USENIS=no
      Whether or not NIS is in use.  If not set, authconfig examines
      the passwd setting in /etc/nsswitch.conf.

USEKERBEROS=no
      Whether or not Kerberos is in use.  If not set, authconfig examines
      the settings in /etc/pam.d/system-auth.
    USELDAPAUTH=no
      Whether or not LDAP is being used for authentication.  If not set,
      authconfig examines the settings in /etc/pam.d/system-auth.  Note
      that this option is separate from USELDAP, and that neither implies
      the other.
    USEMD5=no
      Whether or not MD5-based hashing should be used when setting passwords.
      If not set, authconfig examines the settings in /etc/pam.d/system-auth.
      This option affects authentication using both local files and LDAP.
    USESHADOW=no
      Whether or not shadow passwords are in use.  If not set, authconfig
      checks for the existence of /etc/shadow.
    USESMBAUTH=no
      Whether or not SMB authentication is in use.  If not set, authconfig
      examines the settings in /etc/pam.d/system-auth.

/etc/sysconfig/autofsck

does not normally exist; if it does, it can influence a choice
  whether or not to fsck after a crash

AUTOFSCK_DEF_CHECK=no
      If the user does not respond, choose whether or not to fsck
    AUTOFSCK_SINGLEUSER=
      If this is set, drop to single user mode before fsck.
    
/etc/sysconfig/init:

BOOTUP=<some bootup mode>
     BOOTUP=graphical means use X Windows graphical boot up
     BOOTUP=color means colorized text mode boot display. 
     BOOTUP=verbose means old style display
     Anything else means simplified display, but without color or ANSI-formatting
  LOGLEVEL=<a number>
     Sets the initial console logging level for the kernel.
     The default is 7. 8 means everything (including debugging);
     1 means nothing except kernel panics. syslogd will override
     this once it starts.
  RES_COL=<a number>
     Column of the screen to start status labels at. Defaults to 60
  MOVE_TO_COL=<a command>
     A command to move the cursor to $RES_COL. Defaults to nasty
     ANSI sequences output by echo -e.
  SETCOLOR_SUCCESS=<a command>
     A command to set the color to a color indicating success.
     Defaults to nasty ANSI sequences output by echo -e setting
     the color to green.
  SETCOLOR_FAILURE=<a command>
     A command to set the color to a color indicating failure.
     Defaults to nasty ANSI sequences output by echo -e setting
     the color to red.
  SETCOLOR_WARNING=<a command>
     A command to set the color to a color indicating warning.
     Defaults to nasty ANSI sequences output by echo -e setting
     the color to yellow.
  SETCOLOR_NORMAL=<a command>
     A command to set the color to 'normal'. Defaults to nasty
     ANSI sequences output by echo -e.
  PROMPT=yes|no
     Set to 'yes' to enable the key check for interactive mode as well as
     asking if a filesystem check should be done. Default is 'no' and
     the kernel command line option "forcefsck" can be used to check the
     filesystems and "confirm" can be used to enable interactive startup
     questions.

obsoleted values from earlier releases:

MAGIC_SYSRQ=yes|no
       Setting this to 'no' used to disable the magic sysrq key and
       Stop-A (break on serial console) on SPARC. This setting has been
       moved into kernel.sysrq and kernel.stop-a settings respectively in
       sysctl.d/00-system.conf. Setting either of them there to 0 disables
       it, setting it to 1 enables it.
    STOP_A=yes|no
       Setting this to 'no' used to disable the Stop-A (break on
       serial console) key on SPARC.
       This setting has been moved into kernel.stop-a setting in
       sysctl.d/00-system.conf. Setting it there to 0 disables it,
       setting it to 1 enables it. The setting should be present
       on SPARC only.

/etc/sysconfig/keyboard:

KEYTABLE=<keytable file>
     for example: KEYTABLE="/usr/lib/kbd/keytables/us.map"
    
     If you dump a keymap (using 'dumpkeys') to
	/etc/sysconfig/console/default.kmap
     it will be loaded on bootup before filesystems are mounted/checked.
     This could be useful if you need to emergency type the root password.
     This has to be a dumped keymap, as opposed to copying the shipped
     keymap files, as the shipped files include other maps from the
     /usr/lib/kbd/keytables directory.
     
  KEYBOARDTYPE=sun|pc
    on SPARC only, sun means a sun keyboard is attached on /dev/kbd,
    pc means a PS/2 keyboard is on ps/2 port.
  
/etc/sysconfig/mouse:

In addition, /dev/mouse points to the mouse device.

/etc/sysconfig/network:

NETWORKING=yes|no
  GATEWAY=<gateway IP>
  GATEWAYDEV=<gateway device to use, when multiple devices have GATEWAY=> (e.g. eth0)
  NISDOMAIN=<nis domain name>
  NOZEROCONF=
    Set this to not set a route for dynamic link-local addresses.

NETWORKDELAY=<delay in seconds>
    Delay in seconds after all network interfaces are initialized.  Useful if
    network has spanning tree running and must wait for STP convergence.
    Default: 0 (no delay)

IFDOWN_ON_SHUTDOWN=yes|no
    If yes, do bring interfaces down during system shutdown. If no, leave them
    in their current state (this is only supported on hosts using systemd).
    Default: yes (bring interfaces down)

IPV6FORWARDING=yes|no
    Enable or disable global forwarding of incoming IPv6 packets 
    on all interfaces.
    Note: Actual packet forwarding cannot be controlled per-device, use netfilter6 for such issues
    Default: no

IPV6_AUTOCONF=yes|no
    Sets the default for device-based autoconfiguration.
    Default: yes if IPV6FORWARDING=no, no if IPV6FORWARDING=yes
  IPV6_ROUTER=yes|no
    Sets the default for device-based Host/Router behaviour.
    Default: yes if IPV6FORWARDING=yes, no if IPV6FORWARDING=no
  IPV6_AUTOTUNNEL=yes|no
    Controls automatic IPv6 tunneling.
    Default: no

IPV6_DEFAULTGW=<IPv6 address[%interface]> (optional)
    Add a default route through specified gateway
    An interface can be specified: required for link-local addresses
    Examples:
      IPV6_DEFAULTGW="3ffe:ffff:1234:5678::1"
        Add default route through 3ffe:ffff:1234:5678::1
      IPV6_DEFAULTGW="3ffe:ffff:1234:5678::1%eth0"
        Add default route through 3ffe:ffff:1234:5678::1 and device eth0
      IPV6_DEFAULTGW="fe80::1%eth0"
        Add default route through fe80::1 and device eth0

Note: if IPV6_DEFAULTGW is specified with %interface scope and it
        doesn't match IPV6_DEFAULTDEV, IPV6_DEFAULTDEV is ignored.
  Note: it's preferred to use %interface for all addresses, not
        just link-local if you have multiple IPv6-enabled interfaces.

IPV6_DEFAULTDEV=<interface> (optional)
    Add a default route through specified interface without specifying next hop
    Type of interface will be tested whether this is allowed
    Examples:
      IPV6_DEFAULTDEV="eth0" INVALID example!
      IPV6_DEFAULTDEV="ppp0"
      IPV6_DEFAULTDEV="sit1"
    Examples for 6to4
      IPV6_DEFAULTDEV="tun6to4"
        Add default route through dedicated 6to4 tunnel device "tun6to4", if configured

Note: "tun6to4" does not support an additional IPV6_DEFAULTGW.
        Other interfaces prefer IPV6_DEFAULTGW, if specified.

IPV6_RADVD_PIDFILE=<pid-file> (optional)
    Location of PID file for controlling radvd, see IPV6_CONTROL_RADVD
    Default: "/run/radvd/radvd.pid"
    Example:
       IPV6_RADVD_PIDFILE="/some/other/location/radvd.pid"
  IPV6TO4_RADVD_PIDFILE=<pid-file> (obsolete)
    As above, still supported for a while for backward compatibility.
  IPV6_RADVD_TRIGGER_ACTION=startstop|reload|restart|SIGHUP (optional)
    How to trigger radvd in case of 6to4 or PPP action
     startstop: radvd starts if interface goes up and stops
       if interface goes down using initscript call of radvd with related parameter
     reload|restart: initscript of radvd is called with this parameter
     SIGHUP: signal HUP is sent to radvd, pidfile must be specified, if not the default
    Default: SIGHUP

IPv6 options above can be overridden in interface-specific configuration.

obsoleted values from earlier releases:

FORWARD_IPV4=yes|no
      Create a new file in /etc/sysctl.d/ with the net.ipv4.ip_forward
      setting instead. Setting it to 1 there enables IP forwarding,
      setting it to 0 disables it (which is the default for RFC compliance).

NETWORKWAIT=yes|no
      This is not used with the move to systemd.

HOSTNAME=<fqdn by default, but whatever hostname you want>
      This is now configured in /etc/hostname.

/etc/sysconfig/static-routes-ipv6:
  Contains lines of the form:

<device> IPv6-network IPv6-gateway
    <tunneldevice> IPv6-network

<device> must be a device name to have the route brought up and
  down with the device

For example:
  
  eth0   fec0:0:0:2::/64                         fec0:0:0:1:0:0:0:20
   adds a route for IPv6 network fec0:0:0:2::/64 through fec0:0:0:1:0:0:0:20
   
  eth0    2000::/3	                         3ffe:ffff:0:1::1
   so-called "default" routes for clients

sit1    2000::/3
   adds routes through dedicated tunnel interface sit1

tun6to4  3ffe:ffff:1234::/56			
   adds routes through hardwired 6to4 tunnel interface tun6to4
  tun6to4  3ffe:ffff:5678::/56			::5.6.7.8
   adds routes through hardwired 6to4 tunnel interface tun6to4,
   specifying next hop

Notes:
    * default routes (such as the "2000::/3" shown above) should be set with
       IPV6_DEFAULTGW and IPV6_DEFAULTDEV, see more above.
    * tunnel device "sit0" is not supported here, routes will never be applied

/etc/sysconfig/routed:

SILENT=yes|no
  EXPORT_GATEWAY=yes|no
  
/etc/sysconfig/rawdevices:

This is used for setting up raw device to block device mappings.
  It has the format:
  	<rawdev> <major> <minor>
        <rawdev> <blockdev>
  For example: 
     /dev/raw/raw1 /dev/sda1
     /dev/raw/raw2 8 5

/etc/sysconfig/pcmcia:

PCMCIA=yes|no
  PCIC=i82365|tcic
  PCIC_OPTS=<socket driver (i82365 or tcic) timing parameters>
  CORE_OPTS=<pcmcia_core options>
  CARDMGR_OPTS=<cardmgr options>

/etc/sysconfig/amd:

ADIR=/.automount  (normally never changed)
  MOUNTPTS='/net /etc/amd.conf'  (standard automount stuff)
  AMDOPTS=  (extra options for AMD)

/etc/sysconfig/tape:

DEV=/dev/nst0
    Tape device.  Use the non-rewinding one for these scripts.
  
    For SCSI tapes this is /dev/nst#, where # is the number of the
    tape drive you want to use.  If you only have one then use
    nst0.
 
    For IDE tapes you use /dev/ht#, where # is the number of the tape
    drive you want to use (usually ht0).
 
    For floppy tape drives use /dev/ftape.

ADMIN=root
    Person to mail to if the backup fails for any reason

SLEEP=5
    Time to sleep between tape operations.  Some drives need a bit
    more than others, but 5 seems to work for 8mm, 4mm, and DLT

BLOCKSIZE=32768
    This worked fine for 8mm, then 4mm, and now DLT.  An optimal
    setting is probably however much data your drive writes at one
    time.

SHORTDATE=$(date +%y:%m:%d:%H:%M)
    A short date string, used in backup log filenames.

DAY=$(date +log-%y:%m:%d)
    This is used for the log file directory.

DATE=$(date)
    Regular date string, used in log files.

LOGROOT=/var/log/backup
    Root of the logging directory

LIST=$LOGROOT/incremental-list
    This is the file name the incremental backup will use to store
    the incremental list.  It will be $LIST-{some number}.

DOTCOUNT=$LOGROOT/.count
    For counting as you go to know which incremental list to use

COUNTER=$LOGROOT/counter-file
    For rewinding when done...might not use.

BACKUPTAB=/etc/backuptab
    The file in which we keep our list of backup(s) we want to make.

/etc/sysconfig/saslauthd:

used by the saslauthd init script (part of the cyrus-sasl package) to
  control which arguments are passed to saslauthd at startup time; changes
  made to this file have no effect until saslauthd is restarted

MECH=shadow
    controls which data source saslauthd will consult when checking user
    passwords; run 'saslauthd -v' to get a full list of available
    authentication mechanisms
  SOCKETDIR=/run/saslauthd
    controls in which directory saslauthd will be directed to create its
    listening socket; any change to this value will require a corresponding
    change in client configuration files

/etc/sysconfig/sendmail:
  DAEMON=yes|no
    yes implies -bd (i.e., listen on port 25 for new mail)
  QUEUE=1h
    given to sendmail as -q$QUEUE
    -q option is not given to sendmail if /etc/sysconfig/sendmail
    exists and QUEUE is empty or undefined.

Files in /etc/sysconfig/network-scripts/
========================================

/etc/sysconfig/network-scripts/ifup:
/etc/sysconfig/network-scripts/ifdown:

Symlinks to /sbin/ifup and /sbin/ifdown, respectively.
  These are the only two scripts "in" this directory that should
  be called directly; these two scripts call all the other
  scripts as needed.  These symlinks are here for legacy purposes --
  only /sbin/ifup and /sbin/ifdown should currently be used
  at the user level.

These scripts take one argument normally: the name of the device
  (e.g. eth0).  They are called with a second argument of "boot"
  during the boot sequence so that devices that are not meant to
  be brought up on boot (ONBOOT=no, see below) can be ignored at
  that time.

Also, interfaces may be brought up via the hotplug scripts;
  in this case, HOTPLUG=no needs to be set to no to avoid this.
  This is useful e.g. to prevent bonding device activation by merely
  loading the bonding kernel module.

/etc/sysconfig/network-scripts/init.ipv6-global:
  Not really a public file.  Contains different basic settings that
  are set from /etc/[rc.d]/init.d/network at different stages of
  network initialization.

/etc/sysconfig/network-scripts/network-functions:

Not really a public file.  Contains functions which the scripts use
  for bringing interfaces up and down.  In particular, it contains
  most of the code for handling alternative interface configurations.

/etc/sysconfig/network-scripts/network-functions-ipv6:

Not really a public file.  Contains functions which the scripts use
  for bringing IPv6 on interfaces up and down, like addresses, routes,
  forwarding handling and static or automatic tunneling.

/etc/sysconfig/network-scripts/ifcfg-<interface-name> and
/etc/sysconfig/network-scripts/ifcfg-<interface-name>:<alias-name>:

The first defines an interface, and the second contains
  only the parts of the definition that are different in a
  "alias" (or alternative) interface.  For example, the
  network numbers might be different, but everything else
  might be the same, so only the network numbers would be
  in the alias file, but all the device information would
  be in the base ifcfg file.

The items that can be defined in an ifcfg file depend on the
  interface type.  The really obvious ones I'm not going to
  bother to define; you can figure out what "IPADDR" is, I
  think...  :-)

Base items:
    NAME=<friendly name for users to see>
      Most important for PPP.  Only used in front ends.
    DEVICE=<name of physical device (except dynamically-allocated PPP
      devices where it is the "logical name")>
    IPADDRn=
    PREFIXn=
      Network prefix.  It is used for all configurations except aliases
      and ippp devices.  It takes precedence over NETMASK when both
      PREFIX and NETMASK are set.
    NETMASKn=
      Subnet mask; just useful for aliases and ippp devices.  For all other
      configurations, use PREFIX instead.

The "n" is expected to be consecutive positive integers starting from 0.
    It can be omitted if there is only one address being configured.

GATEWAY=
    METRIC=
      Metric for the default route using GATEWAY
    ONBOOT=yes|no (not valid for alias devices; use ONPARENT)
    HOTPLUG=yes|no
    USERCTL=yes|no
    BOOTPROTO=none|bootp|dhcp
      'bootp' or 'dhcp' cause a DHCP client to run on the device. Any other
      value causes any static configuration in the file to be applied.
    VLAN=yes|no
    MTU=
      Default MTU for this device
    WINDOW=
      Default window for routes from this device
    PEERDNS=yes|no
      modify /etc/resolv.conf if peer uses msdns extension (PPP only) or
      DNS{1,2} are set, or if using dhclient. default to "yes".
    DNS{1,2}=<ip address>
      provide DNS addresses that are dropped into the resolv.conf
      file if PEERDNS is not set to "no".
    SCOPE=
      Set to "scope SCOPE-ID" to set a non-default scope for a statically
      configured IP address.
    SRCADDR=
      use the specified source address for outgoing packets
    HWADDR=
      ethernet hardware address for this device
    MACADDR=
      Set the hardware address for this device to this.
      Use of this in conjunction with HWADDR= may cause
      unintended behavior.
    NOZEROCONF=
      Set this to not set a route for dynamic link-local addresses
      over this device.
    LINKSTATUS=up|down
     Setting LINKSTATUS to down prevents network-scripts from bringing up interface.
     This prevents issues with interfaces like Open vSwitch bridges which uses
     userspace datapaths. If not set defaults to up.
    PERSISTENT_DHCLIENT=yes|no|1|0
      Without this option, or if it is 'no'/'0', and BOOTPROTO=dhcp,
      dhclient is run for the interface in "one-shot" mode; if the 
      dhcp server does not respond for a configurable timeout, then
      dhclient exits and the interface is not brought up - 
      the '-1' option is given to dhclient.
      If PERSISTENT_DHCLIENT=yes, then dhclient will keep on trying
      to contact the dhcp server when it does not respond - no '-1'
      option is given to dhclient. Note: this disables the automatic
      checking for the presence of a link before starting dhclient.
    DHCPRELEASE=yes|no|1|0
      With this option set to 'yes' (1), when a dhcp configured
      interface is brought down with 'ifdown', the lease will be
      released. Otherwise, leases are not released.

NO_DHCP_HOSTNAME=yes|no|1|0
      Tells initscripts to not obtain hostname from DHCP server in the ifup-post
      phase. This option might be useful especially with static configuration of
      the interface.
    DHCP_SEND_HOSTNAME=yes|no|1|0
      Tells initscripts whether the DHCP_HOSTNAME or DHCP_FQDN options (below)
      should be sent to DHCP server.
    DHCP_HOSTNAME=<hostname>
      Sends the specified hostname to the DHCP server.
    DHCP_FQDN=<fully.qualified.domain.name>
      Sends the specified FQDN to the DHCP server.

Please note when both DHCP_HOSTNAME and DHCP_FQDN are specified,
    only DHCP_FQDN will be used. (Same behaviour as with NetworkManager.)

DHCLIENT_IGNORE_GATEWAY=yes|no|1|0
      If set to 'yes', it will cause dhclient-script to ignore any $GATEWAY
      setting that may be in the ifcfg file for this interface.
      Otherwise, the dhclient session which obtains an ip-address
      on the same subnet as $GATEWAY will set the default route
      to be via $GATEWAY, and no other dhclient session will set
      the default route.
    DHCLIENTARGS=
      Any additional arguments to dhclient.
    NM_CONTROLLED=yes|no
      If set to 'no', NetworkManager will ignore this connection/device.
      Defaults to 'yes'.
    ZONE=
      Network zone (trust level) of this connection.
      If not set, default zone (specified in /etc/firewalld/firewalld.conf)
      is used. To see all available zones, run 'firewall-cmd --get-zones'.
    ARPCHECKn=yes|no
      If set to 'no', ifup will not try to determine, if requested ip address
      is used by other machine in network.
      Defaults to 'yes'.
    ARPING_WAIT=<number>
      Number of seconds for which will be arping trying to determine, if requested ip
      address is used in network. This option works with ARPCHECKn=yes
      If not set default is 3 sec.  
      example: ARPING_WAIT=1
    ARPUPDATE=yes|no
      If set to 'no' the neighbours in current network will not be updated with
      ARP information about this NIC. This is especially handy using LVS Load
      Balancing with Direct Routing enabled.
      Defaults to 'yes'.
    ARPING_UPDATE_WAIT=<number>
      Number of seconds for which will be arping trying to update arp cache
      of neighbours with ARP informations about this NIC.
      This option works with ARPUPDATE=yes. If not set default is 3 sec.  
      example: ARPING_UPDATE_WAIT=1
    IPV4_FAILURE_FATAL=yes|no
      If set to yes, ifup-eth will end immediately after ipv4 dhclient fails.
      Defaults to 'no'.

For dynamic addressing (BOOTPROTO=dhcp) only DEVICE needs to
  be set; all the rest will be determined by the boot protocol.

IPV6_SET_SYSCTLS=yes|no
      If set, network-scripts will attempt to set sysctls based on the setup
      of the interface. For example, will try to set `accept_ra` for interfaces
      where $IPV6_AUTOCONF is set to `yes`. Defaults to `yes`, set to `no` if you
      want to manage these yourself.

Base items being deprecated:
    NETWORK=<will be calculated automatically with ipcalc>
    BROADCAST=<will be calculated automatically with ipcalc>

Alias specific items:
    ONPARENT=yes|no
      Whether to bring up the device when the parent device is brought
      up.
      Default: yes

IPv6-only items for real interfaces:
    IPV6INIT=yes|no
      Enable or disable IPv6 static, DHCP, or autoconf configuration for this interface
      Default: yes
    IPV6FORWARDING=yes|no
      Enable or disable global forwarding of incoming IPv6 packets
      Note: Obsolete in interface specification!
      Default: no
    IPV6ADDR=<IPv6 address>[/<prefix length>]
      Specify a primary static IPv6 address here
      Optional, if normal host and a router advertisement daemon is on local link
      Required, if node is a router and interface should route packets
      Note: if prefix length is omitted, 64 is assumed
      Example:
        IPV6ADDR="3ffe:ffff:0:5::1"
        IPV6ADDR="3ffe:ffff:0:1::1/128"
    IPV6ADDR_SECONDARIES="<IPv6 address>[/<prefix length>] ..." (optional)
      A list of secondary IPv6 addresses (e.g. useful for virtual hosting)
      Example:
        IPV6ADDR_SECONDARIES="3ffe:ffff:0:1::10 3ffe:ffff:0:2::11/128"
    IPV6_MTU=<MTU of link> (optional)
      Optional, dedicated MTU of this link
      Note: Must be greater or equal to 1280.
      Example:
        IPV6_MTU="1280"
    IPV6_PRIVACY=rfc3041
      Enables RFC 3041 IPv6 privacy support if set.
      Default: RFC 3041 support disabled
    IPV6_FORCE_ACCEPT_RA=yes|no
      By default network-scripts will set `accept_ra` only if $IPV6_AUTOCONF is
      set to `yes`. If you don't want SLAAC addresses but do want to accept RA,
      then set this to `yes`. Defaults to `no`.

Special configuration options for multi-homed hosts etc.
	IPV6_ROUTER=yes|no: Controls IPv6 autoconfiguration
	IPV6_AUTOCONF=yes|no: Controls IPv6 autoconfiguration
	 Defaults:
	  Global IPV6FORWARDING=yes: IPV6_AUTOCONF=no, IPV6_ROUTER=yes
	  Global IPV6FORWARDING=no: IPV6_AUTOCONF=yes

Optional settings for a 6to4 tunnel
    IPV6TO4INIT=yes|no
      Enable or disable 6to4 tunneling setup
      Default: no
    IPV6TO4_RELAY=<IPv4 address> (optional)
      IPv4 address of the remote 6to4 relay
      Note: if this is omitted, ::192.88.99.1 (the anycast relay address) is chosen
    IPV6TO4_IPV4ADDR=<IPv6 address>[/<prefix length>] (optional)
      Overwrite local IPv4 address which is accessible from the Internet
       (optional, in case of static IPv4-NAT behind a router or other special scenarios)
    IPV6TO4_MTU=<MTU for IPv6> (optional)
      Controls IPv6 MTU for the 6to4 tunnel
      Note: Must be greater or equal to 1280
      Example:
        IPV6TO4_MTU="1280"
      Default: MTU of master device - 20
    IPV6TO4_ROUTING="<device>-<suffix>/<prefix length> ..." (optional)
      A list of routing tokens to setup proper IPv6 interfaces on the LAN
      Example:
         IPV6TO4_ROUTING="eth0-:0004::1/64 eth1-:0005::1/64"
         Will create one address per eth0 and eth1, taking given SLA

Optional settings for a 6to4 tunnel or a ppp link
    IPV6_CONTROL_RADVD=yes|no (optional)
      Enable signaling radvd that the 6to4 prefix has been changed or a
       preconfigured dynamic device is up or down
      Default: no

IPv6-only items for static tunnel interface:
    Interface name: sitX (X => 1)
    IPV6INIT=yes|no
      Enable or disable IPv6 configuration for this interface
      Default: no
    IPV6TUNNELIPV4=<IPv4 address>
      Specify IPv4 address of a foreign IPv6-in-IPv4 tunnel endpoint
      Example:
        IPV6TUNNELIPV4="1.2.3.4"
    IPV6TUNNELIPV4LOCAL=<IPv4 address>
      Specify local IPv4 address of tunnel, useful on interfaces with multiple IPv4 addresses
    IPV6ADDR=<IPv6 address>[/<prefix length>] (optional)
     local IPv6 address of a numbered tunnel
    IPV6ADDR_SECONDARIES="<IPv6 address>[/<prefix length>] ..." (optional)
      A list of secondary IPv6 addresses (example see above)
    IPV6_MTU=<MTU of tunnel> (optional)
      Optional, dedicated MTU of this tunnel
      Note: Must be greater or equal to 1280
      Example:
        IPV6_MTU="1280"

IPv6-only option to enable DHCPv6 client:
      DHCPV6C=yes|no
      This will enable the DHCPv6 features of dhclient to be run for the interface.
      See man dhclient(8) and dhclient.conf(5).
      DHCPV6C_OPTIONS=...
      This will pass given arguments to the DHCPv6 client.  For example,
      "-S" option will request network information (e.g., DNS addresses)
      only, not IPv6 addresses.

Ethernet-only items:
    ARP=yes|no (adds 'arp' flag to ip, for use with the
      ethertap device)
    LINKDELAY=<time in seconds>
      Time that the system should pause after the specific interface is
      enabled.  This may be useful if one interface is connected to a
      switch which has spanning tree enabled and must wait for STP to
      converge before the interface should be considered usable.
    BRIDGE=<br* device>
      If set, the ethernet device is not assigned an address.  It is added to
      the specified bridge device instead.
    EXTRA_ROUTE_OPTS=<string of route options>
      Extra options to add to the interface route. For example, let's say you
      wanted an interface route to have an mtu of 1480, but wanted the
      interface to still have a route of 1500, you could set "mtu 1480" here.
      Anything here is appended to the `ip route add` or `ip route replace`
      command.

Deprecated, but supported:
    ETHTOOL_OPTS=...
      Any device-specific options supported by ethtool. For example,
      if you wanted to force 100Mb full duplex:
        ETHTOOL_OPTS="speed 100 duplex full autoneg off"
      Note that changing speed or duplex settings almost always
      requires disabling autonegotiation with 'autoneg off'.

Multiple options can also be set like so :
      ETHTOOL_OPTS="-K ${DEVICE} tso on; -G ${DEVICE} rx 256 tx 256"

Long term, this should be done by sysadmin-written udev rules.

No longer supported:
     PROMISC=yes|no (enable or disable promiscuous mode)
     ALLMULTI=yes|no (enable or disable all-multicast mode)
     
     To properly set these, use the packet socket interface.

Ethernet 802.1q VLAN items:
     DEVICE=eth0.42
       Initscripts use the device name for VLAN devices.
               Example: eth0.42 for vlan 42 on device eth0.
       Valid VLAN ID range is 0-4095. Most ethernet switches reserve
       VLAN ID 1 to be used as management VLAN; starting from VLAN
       ID 2 is recommended.
     REORDER_HDR=yes|no
       When enabled the VLAN device will move the ethernet header
       around to make it look exactly like a real ethernet device.
       This may help programs such as ISC dhcpd which read the raw
       ethernet packet and make assumptions about the location of
       bytes. If you don't need it turn it off because there
       is a small performance penalty. Default is on.
     GVRP=yes|no
       When enabled, this will announce new vlan creation to a GVRP
       enabled trunk port on a switch. Default is off.

PPP/SLIP items:
    PERSIST=yes|no
    MODEMPORT=<device, say /dev/modem>
    LINESPEED=<speed, say 115200>
    DEFABORT=yes|no (tells netcfg whether or not to put default
      abort strings in when creating/editing the chat script and/or
      dip script for this interface)
      (meaningless with WVDIALSECT)
 
  PPP-specific items
    WVDIALSECT=<list of sections from wvdial.conf to use>
      If this variable is set, then the chat script (if it
      exists) is ignored, and wvdial is used to open the
      PPP connection.
    DEFROUTE=yes|no (set this interface as default route? yes is default)
    DEBUG=yes|no (defaults to yes)
      turns on/off pppd and chat (if used) debugging.
    ESCAPECHARS=yes|no (simplified interface here doesn't let people
      specify which characters to escape; almost everyone can use
      asyncmap 00000000 anyway, and they can set PPPOPTIONS to
      asyncmap foobar if they want to set options perfectly)
    HARDFLOWCTL=yes|no (yes implies "modem crtscts" options)
    PPPOPTIONS=<arbitrary option string; is placed last on the
      command line, so it can override other options like asyncmap
      that were specified differently>
    PPPOE_EXTRA = any extra arguments to pass to pppoe 
    PPPD_EXTRA =  any extra arguments to pass to pppd 
    PAPNAME=<"name $PAPNAME" on pppd command line> (note that
      the "remotename" option is always specified as the logical
      ppp device name, like "ppp0" (which might perhaps be the
      physical device ppp1 if some other ppp device was brought
      up earlier...), which makes it easy to manage pap/chap
      files -- name/password pairs are associated with the
      logical ppp device name so that they can be managed
      together.
    REMIP=<remote ip address, normally unspecified>
    MTU=
    MRU=
    DISCONNECTTIMEOUT=<number of seconds, default currently 5>
      (time to wait before re-establishing the connection after
      a successfully-connected session terminates before attempting
      to establish a new connection.)
    RETRYTIMEOUT=<number of seconds, default currently 60>
      (time to wait before re-attempting to establish a connection
      after a previous attempt fails.)
    RETRYCONNECT=yes|no (defaults to yes)
      If this is yes, then we will re-run pppd if it exits with a 
      "connect script failed" status.  Otherwise, only one attempt
      is made to bring up the connection.  Note that some connect
      scripts (for example, wvdial) might do their own retries (such
      as BUSY or NO DIALTONE conditions).
    MAXFAIL=<number>
      If this is set, this will cause ppp-watch to exit after
      the specified number of attempts.
    DEMAND=yes|no
      Switches on demand-dialing mode using pppd's "demand" option.
    IDLETIMEOUT=600
      The amount of time the link needs to be inactive before pppd will
      bring it down automatically.
    BOOTTIMEOUT=30
      The amount of time to wait at boot before giving up on the
      connection.

IPPP-specific items (ISDN)
    PROVIDER=<ProviderName>
	 USER=<Login>
    PASSWORD=<Password>
	 ENCAP=[syncppp|]
    DIALMODE=[manual|auto]
    SECURE=off|on
	 MSN=<>
	 PHONE_IN=<Callback.Number>
	 	 AREACODE=<>
	 REGIONCODE=<>
	 PHONE_OUT=<PhoneNumber>
    BUNDLING=off|on
    HUPTIMEOUT=<number>
    DNS1=<PrimaryDNS>
    DNS2=<SecondaryDNS>
    DOMAIN=""
    LAYER=[HDLC|]
    CALLBACK=off|on
    CHARGEHUP=<number>
    CHARGEINT=<number>
    CBHUP=<number>
    CBDELAY=<number>
    DIALMAX=<number>
    AUTH=[+pap] [-chap]
    IHUP=<>
    DELDEFAULTROUTE=[enabled|disabled]
    CBCP=off|on
    VJ=off|on
    VJCCOMP=off|on
    AC=off|on
    PC=off|on
    BSDCOMP=off|on
    CCP=off|on
    SLAVE_DEVICE=ippp[0-9]

ippp0 items being deprecated:
    BOOT=[on|off] will be converted to ONBOOT=[yes|no] by netconf
    LOCAL_IP=     will be converted to IPADDR by netconf
    REMOTE_IP=    will be converted to GATEWAY by netconf

Wireless-specific items:
    See iw(8) for additional information.
    MODE=[Managed|Ad-Hoc|Monitor]
    ESSID=
      Required.
    FREQ=
      Required if MODE=Ad-Hoc.
    KEY=<default WEP key>

IPSEC specific items
     SRC=source address. Not required.
     DST=destination address
     TYPE=IPSEC
     SRCNET=source net (for tunneling)
     DSTNET=destination network (for tunneling)

Manual keying:

AH_PROTO{,_IN,_OUT}=protocol to use for AH (defaults to hmac-sha1)
     ESP_PROTO{,_IN,_OUT}=protocol to use for ESP (defaults to 3des-cbc)
     AESP_PROTO{,_IN,_OUT}=protocol to use for ESP authentication (defaults to
	hmac-sha1)
     KEY_AH{,_IN,_OUT}=AH key
     KEY_ESP{,_IN,_OUT}=ESP encryption key
     KEY_AESP{,_IN,_OUT}=ESP authentication key (optional)
     SPI_{ESP,AH}_{IN,OUT}=SPIs to use

_IN and _OUT specifiers are for using different keys or protocols for
   incoming and outgoing packets.  If neither _IN or _OUT variants are set for
   protocols or keys, the same will be used for both.  Hexadecimal keys need to
   be prefixed with "0x".

Automatic keying:

IKE_DHGROUP=<number> (defaults to 2)
     IKE_METHOD=PSK|X509|GSSAPI
         PSK=preshared keys (shared secret)
         X509=X.509 certificates
         GSSPI=GSSAPI authentication
     IKE_AUTH=protocol to use for Phase 1 of SA (defaults to sha1)
     IKE_ENC=protocol to use for Phase 1 of SA (defaults to 3des)
     IKE_PSK=preshared key for this connection
     IKE_CERTFILE=our certificate file name for X509 IKE
       IKE_PEER_CERTFILE=peer public cert filename for X509 IKE
       IKE_DNSSEC=retrieve peer public certs from DNS
     (otherwise uses certificate information sent over IKE)

To manage the racoon configuration manually (e.g. when there is more than
     one IPSEC configuration with the same DST), set KEYING=automatic and leave
     all IKE_* parameters unspecified.

To override the identifier to use with a preshared key:

MYID_TYPE=address|fqdn|user_fqdn
       MYID_VALUE=fqdn or user_fqdn string for this connection

Usage of AH or ESP may be disabled by setting {AH,ESP}_PROTO to "none".

Bonding-specific items

SLAVE=yes
      Specifies device as a slave
    MASTER=bondXX
      Specifies master device to bind to
    BONDING_OPTS=
      A space-separated list of options to the bonding driver for this
      interface, such as:

"mode=active-backup arp_interval=60 arp_ip_target=192.168.1.1,192.168.1.2"

Tunnel-specific items:
    TYPE=GRE|GRE6|IPIP|IPIP6|EXTERNAL
      External is a mode for ip6_tunnel interfaces (that cannot be set on
      the primary ip6tnl0 interface), which permits unwrapping encapsulated
      packets regardless of their internal IP (v4 or v6) provided the inner
      address is on the interface. Use $MY_INNER_IPADDR for v4 addresses. Use
      $IPV6ADDR and $IPV6ADDR_SECONDARIES as usual for v6 addresses.
    MY_INNER_IPADDR=local IP address of the tunnel interface
    PEER_OUTER_IPADDR=IP address of the remote tunnel endpoint
    MY_OUTER_IPADDR=IP address of the local tunnel endpoint
      If unspecified, an IP address is selected automatically for outgoing
      tunnel packets, and incoming tunnel packets are accepted on all local
      IP addresses.
    PEER_INNER_IPADDR=IP address of the remote end of the tunnel interface
      If this is specified, a route to PEER_INNER_IPADDR through the tunnel
      is added automatically.
    TTL=TTL value for tunnel packets
      Default is to use the TTL of the packet transported through the tunnel

Bridge-specific items:
    TYPE=Bridge
    STP=off|on (see 'brctl stp')
    DELAY=forward delay time in seconds (see 'brctl setfd')
    BRIDGING_OPTS=
      A space-separated list of bridging options for either the bridge
      device, or the port device, such as:

BRIDGING_OPTS="hello_time=200 priority=65535"
        for bridge devices, or
      BRIDGING_OPTS="hairpin_mode=1"
        for port devices.

TUN/TAP-specific items:
    OWNER=<owner of the device>

/etc/sysconfig/network-scripts/chat-<interface-name>:

chat script for PPP or SLIP connection intended to establish
  the connection.  For SLIP devices, a DIP script is written
  from the chat script; for PPP devices, the chat script is used
  directly.

/etc/sysconfig/network-scripts/dip-<interface-name>

A write-only script created from the chat script by netcfg.
  Do not modify this.  In the future, this file may disappear
  by default and created on-the-fly from the chat script if
  it does not exist.

/etc/sysconfig/network-scripts/ifup-post

Called when any network device EXCEPT a SLIP device comes
  up.  Calls /etc/sysconfig/network-scripts/ifup-routes to
  bring up static routes that depend on that device.  Calls
  /etc/sysconfig/network-scripts/ifup-aliases to bring up
  aliases for that device.  Sets the hostname if it is not
  already set and a hostname can be found for the IP for that
  device.  Sends SIGIO to any programs that have requested
  notification of network events.

Could be extended to fix up nameservice configuration, call
  arbitrary scripts, etc, as needed.

/etc/sysconfig/network-scripts/ifup-routes

Set up static routes for a device.

/etc/sysconfig/network-scripts/ifup-aliases

Bring up aliases for a device.

/etc/sysconfig/network-scripts/route-<interface-name>

Contains lines that specify additional routes that should be added when the
  associated interface is brought up.

The files are processed by the ifup-routes script and uses the /sbin/ipcalc
  utility for all network masks and numbers. Routes are specified using the
  syntax:

ADDRESSn=<network>
    NETMASKn=<network/prefix mask>
    GATEWAYn=<next-hop router/gateway IP address>

The "n" is expected to be consecutive positive integers starting from 0.
  For example:

ADDRESS0=192.168.2.0
    NETMASK0=255.255.255.0
    GATEWAY0=192.168.1.1

adds a network route to the 192.168.2.0 network via the gateway at
  192.168.1.1. Since you must already have a route to the network of the
  gateway, there is no need to specify a device.

Note: The ifup-routes script also supports an older syntax designed to be
  used directly as an argument to "/sbin/ip route add".
  If no "ADDRESSn" lines are found the following will still
  work:
  
  192.168.2.0/24 dev ppp0
  
  adds a network route to the 192.168.2.0 network through ppp0.

/etc/sysconfig/network-scripts/route6-<interface-name>

Contains lines that are arguments to "/sbin/ip -6 route add"
  For example:

site-local route for network fec0:0:0:2::/64
   via gateway fec0:0:0:1:0:0:0:20 (e.g. on eth0):

fec0:0:0:2::/64 via fec0:0:0:1:0:0:0:20

additional prefix configured to be on-link on eth0:

3ffe:fffe:1:2::/64 dev eth0
  
  6to4 route for network 3ffe:ffff:1::/48, either:

3ffe:ffff:1::/48
  3ffe:ffff:1::/48 via ::192.168.1.2

Note the special case of 6to4 interface: 'via [relay]' is 
  automatically added if explicit 'via' wasn't specified.

/etc/sysconfig/network-scripts/rule-<interface-name>
/etc/sysconfig/network-scripts/rule6-<interface-name>

Contains lines that specify additional routing rules that should be added
  when the associated interface is brought up.

Each non-comment line is used directly as an argument to "/sbin/ip rule add"
  or "/sbin/ip -6 rule add" for rule6 files.

MR SKB