rc-scripts files:
========================================

/sbin/ifup:
/sbin/ifdown:

  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 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.

/sbin/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
  and interface change notification through netreport.

/lib/rc-scripts/ifup-post

  Called when any network device EXCEPT a SLIP (with dip) device comes
  up.  Calls /lib/rc-scripts/ifup-routes to
  bring up static routes that depend on that device.  Calls
  /sbin/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.

/lib/rc-scripts/ifup-routes

  Set up static routes for a device.

/lib/rc-scripts/ifup-aliases

  Bring up aliases for a device.

/lib/rc-scripts/ifdhcpc-done

  Called by dhcpcd once dhcp configuration is complete; sets
  up /etc/resolv.conf from the version dhcpcd dropped in
  /etc/dhcpc/resolv.conf
  
Files in /etc/sysconfig/interfaces/
========================================

/etc/sysconfig/interfaces/ifcfg-<interface-name> and
/etc/sysconfig/interfaces/ifcfg-<interface-name>-<clone-name>:

  The first defines an interface, and the second contains
  only the parts of the definition that are different in a
  "clone" (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 clone 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:
    DEVICE=<name of physical device (except dynamically-allocated PPP
      devices where it is the "logical name")
    IPADDR=		IP_AOPTS=	IP_ROPTS=	IP_LABEL=
    IPADDR1=		IP_AOPTS1=	IP_ROPTS1=	IP_LABEL1=
    IP_ADDRx=		IP_AOPTSx=	IP_ROPTSx=	IP_LABELx=
    IP4_PRIM_IF=	IP4_SRC_IF=
    IP6_PRIM_IF=
    GATEWAY=
    ONBOOT=yes|no
    USERCTL=yes|no
    BOOTPROTO=none|bootp|dhcp|pump|zeroconf|auto
    ETHTOOL_OPTS=

  If BOOTPROTO is not "none", then the only other item that
  must be set is the DEVICE item; all the rest will be determined
  by the boot protocol.  No "dummy" entries need to be created.

  Ethernet-only items:
    {IPXNETNUM,IPXPRIMARY,IPXACTIVE}_{802_2,802_3,ETHERII,SNAP}
    configuration matrix for IPX.  Only used if IPX is active.
    Managed from /lib/rc-scripts/ifup-ipx

  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'.

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

  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)
 
  PPP-specific items
    DEFROUTE=yes|no (set this interface as default route?)
    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 imples "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>
    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.

      In principal, I'm not aware of anything that would keep
      the logical PPP device names from being "worldnet" or
      "myISP" instead of ppp0-pppN)
    REMIP=<remote ip4 address, normally unspecified>
    REMIP6=<remote ip6 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.)
    INITSCRIPT=<modem command>
      string which initialises your modem. Usualy something like 
      AT&F0&C1&D2
      (TLD Linux rc-scripts specific option)
    DATAFORCHAT=<list of variables>
      List of variables which should be exported to chat script.
      Used mostly for passing USERNAME and PASSWORD into it. (see below)
      (TLD Linux rc-scripts specific option)
    PEERDNS=yes|no
    IPV6_PPP=yes|no
      use IPv6 for ppp
       IPV6_CP_USEV4=yes|no
         use local IPv4 mapped addresses as IPv6 addresses
       IPV6_CP_PERSISTENT=yes|no
         use EUI-48 addresses as IPv6 addresses
       or by default use address specified by IP6_PRIM_IF and REMIP6
    ENABLE_6TO4=yes|no
      configure a 6to4 tunnel, if the interface has a public
      (non-RFC1918) IPv4 address
    <anything>=<anything>
      Variable name and it's value for use by chat script.
      Note: You don't have to define variables here, if they are defined 
      in parent process enviroment they will be used.
      in.ex. USERNAME usualy is. 
  
  IPIP/GRE/SIT tunnel-specific items
    REMOTEIP=<ip_addres>
      address of the remote end of tunnel
    LOCALIP=<ip_addres>
      address of the local end of tunnel
      


/etc/sysconfig/interfaces/ifcfg-<interface-name>-<anything>!:

  Template or backup file. This will not be interpreted
  by net-scripts.

/etc/sysconfig/interfaces/data/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.
  In TLD Linux version of rc-scripts, this file is parsed by shell
  (actually by grep in firstplace to get rid of comments) before it
  is passed to chat.
  This allows you to substitute shell variables with their values 
  defined in <interface name> or more generally in current env.
  If You wonder about purbose, imagine one chat-script for all links 
  at ISP's border router or computer in home where all users have own IPS's
  accounts and want to pay only for themselfes.
  Unfortunetly this parsing have impact on chat script syntax.
  All characters that have special meaning for shell have to be escaped.
  
  
/etc/sysconfig/interfaces/data/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.