IFCFG-TUNNEL(5) 					       Network configuration						   IFCFG-TUNNEL(5)

NAME

       ifcfg-tunnel - network tunnel interface configuration

SYNOPSIS

       /etc/sysconfig/network/ifcfg-gre*
       /etc/sysconfig/network/ifcfg-ipip*
       /etc/sysconfig/network/ifcfg-sit*

       /etc/sysconfig/network/ifcfg-tun*
       /etc/sysconfig/network/ifcfg-tap*

Tunnel interfaces
       It is possible to create static IP tunnel interfaces for three different protocols:
	      SIT    IPv6 over IPv4 tunnel
	      GRE    universal IPv4 tunnel
	      IPIP   IPv4 over IPv4 tunnel

       Additionally, also creation of user space program driven tunnels using the universal TUN/TAP device driver is supported:
	      TAP    Ethernet tunnel interface
	      TUN    Point-to-Point IP tunnel interface

       Since there is not yet a YaST2 support for creating tunnels one must write appropriate config files by hand for now.

VARIABLES

       These variables can used in ip tunnel config files:

       TUNNEL Here  you  have to set the tunnel protocol. This may be "sit" for IPv6 over IPv4 tunnel, "gre" for universal IPv4 tunnel, "ipip" for
	      IPv4 over IPv4 tunnel and "tap" or "tun" for the user space program driven tunnels.

       TUNNEL_LOCAL_IPADDR or TUNNEL_DEVICE
	      The address of the local tunnel's end could be directly specified in TUNNEL_LOCAL_IPADDR variable. The address must be present on an
	      existing interface of this host (the TUNNEL_DEVICE). If TUNNEL_LOCAL_IPADDR is empty the first ipv4 address from the interface given
	      in the variable TUNNEL_DEVICE will be used.

       TUNNEL_REMOTE_IPADDR
	      The address of the remote tunnel's end.

       TUNNEL_TTL
	      Specify the Time To Life of the packet which carries the tunneled data. Usually it is set to 64 but in some  circumstances  you  may
	      want  do	use something else between 1 and 255. Special value is "inherit" in which case the TTL is copied from the inner (tunneled)
	      packet. This is also the default if the TTL variable wasn't used.

       TUNNEL_OPTIONS
	      Here you may set additional options for the command ip tunnel add

       TUNNEL_SET_PERSISTENT
	      Create a persistent tun or tap interface. Default is "yes".  Non-persistent tunnels are not supported yet.

       TUNNEL_SET_OWNER and TUNNEL_SET_GROUP
	      Allows to set the owner and group (by name or UID/GID) for persistent tun/tap interfaces.

Examples for tunnel configurations
       This are some generic examples for different tunnel types. Replace the shown addresses and interface names by your individual ones. As con-
       figuration names you may choose the interface names.

       GRE and IPIP tunnels
	      Create a GRE tunnel between a local computer with IP address 192.168.1.2 and a remote computer with IP address 172.16.2.3. After the
	      tunnel is created assign an IP address 10.20.30.40 to it's local end. Default filename: ifcfg-gre1
		 STARTMODE='onboot'
		 BOOTPROTO='static'
		 TUNNEL='gre'
		 TUNNEL_LOCAL_IPADDR='192.168.1.2'
		 TUNNEL_REMOTE_IPADDR='172.16.2.3'
		 IPADDR='10.20.30.40'
		 TUNNEL_TTL='64'

	      IPIP tunnel is created in exactly the same way, except that the variable TUNNEL has to be set to "ipip" in this case.  Use  filename
	      ifcfg-tunl1 in this case.

       SIT tunnels for IPv6 over IPv4
	      There are two modes in which SIT tunnels may operate: static and 6to4

	      To create a "static" tunnel one needs to know an IPv4 address of the remote end, while for a "6to4" tunnel the remote end is a "6to4
	      relay". These relays are usually public and could be reached either under their respective IPv4 address or under a unique IPv4  any-
	      cast address 192.88.99.1 (as defined in RFC 3068).

	      This typical config file for a 6to4 tunnel should fit most user's needs and the only required change is the external interface name.
	      Default filename: ifcfg-sit1
		 STARTMODE='onboot'
		 BOOTPROTO='6to4'
		 TUNNEL='sit'
		 TUNNEL_DEVICE='eth0'
		 TUNNEL_TTL='64'
	      Additionally you need to set some routes. Do that in a file called ifroute-<configname> with the same configname as  in  ifcfg-<con-
	      figname>. Default filename: ifroute-sit1 It may look like this:
		 2000::/3  2002:c058:6301::1  -  -  -  metric 1
	      The magic string 2002:c058:6301::1 is a 6to4 version of the anycast IPv4 address 192.88.99.1.

	      To create a "static" tunnel with local IPv6 address 3ffe:ffff::1234/64 use a config file like this: Default filename: ifcfg-sit1
		 STARTMODE='onboot'
		 BOOTPROTO='static'
		 TUNNEL='sit'
		 TUNNEL_LOCAL_IPADDR='192.168.1.2'
		 TUNNEL_REMOTE_IPADDR='172.16.2.3'
		 IPADDR='3ffe:ffff::1234/64'
		 TUNNEL_TTL='64'

       Universal TUN/TAP tunnels
	      The  universal TUN/TAP kernel driver provides an interface for user space programs to operate a tunnel. There are two modes in which
	      the interface can be created:
		TUN (a Point-to-Point interface using local and remote IP) or
		TAP (like normal ethernet interface, e.g. for use in bridges).

	      The following configuration allows to create the interfaces persistently:

	      ifcfg-tap0
		 STARTMODE='onboot'
		 BOOTPROTO='static'
		 TUNNEL='tap'
		 # optionally:
		 TUNNEL_SET_PERSISTENT='yes'
		 TUNNEL_SET_OWNER='username'
		 TUNNEL_SET_GROUP='groupname'

	      ifcfg-tun0
		 STARTMODE='onboot'
		 BOOTPROTO='static'
		 TUNNEL='tun'
		 # optionally:
		 TUNNEL_SET_PERSISTENT='yes'
		 TUNNEL_SET_OWNER='username'
		 TUNNEL_SET_GROUP='groupname'

	      The user space program can be started later, e.g. by the ifservices(5) mechanism. The TUNNEL_SET_OWNER and TUNNEL_SET_GROUP settings
	      allow  to  run the user space program with an different UID/GID than 0 (root). When not specified, the user space program has to run
	      with UID 0.

	      Non-persistent tunnels (TUNNEL_SET_PERSISTENT=no), where the user space program (e.g. openvpn) is started directly in ifup, are  not
	      supported yet.

BUGS

       Please report bugs at <http://www.suse.de/feedback>

AUTHOR

       Christian Zoz <zoz@suse.de> -- ifup script
       Michal Svec <msvec@suse.cz> -- ifup script
       Bjoern Jacke -- ifup script
       Mads Martin Joergensen <mmj@suse.de> -- ifup manual page
       Michal Ludvig <mludvig@suse.cz> -- tunnel support

SEE ALSO

       ifcfg(5), ifup(8).

sysconfig							    August 2004 						   IFCFG-TUNNEL(5)