Technical data

4. Packages
IPV6_TUNNEL_x_REMOTEV4 This variable contains the remote IPv4-address of the tun-
nel. Usually this value is given to you by the tunnel provider.
Example (as used by PoP deham01 by Easynet):
IPV6_TUNNEL_1_REMOTEV4='212.224.0.188'
Important: If PF_INPUT_ACCEPT_DEF is set to “no” (the IPv4-firewall is configured man-
ually) you will need a firewall rule to accept all IPv6-in-IPv4 packets (IP-Protokoll 41)
from the tunnel endpoint. For the tunnel endpoint above the rule would be like this:
PF_INPUT_x='prot:41 212.224.0.188 ACCEPT'
IPV6_TUNNEL_x_LOCALV6 This variable sets the local IPv6 address of the tunnel includ-
ing the used netmask in CIDR notation. This information is predetermined from the
tunnel provider. This information is unnecessary for tunnel providers which re-assign
the tunnel endpoints for establishing the tunnel new each time (Such Providers are not
yet supported).
Example: IPV6_TUNNEL_1_LOCALV6='2001:db8:1743::2/112'
IPV6_TUNNEL_x_REMOTEV6 This variable specifies the remote IPv6 address of the tun-
nel. This information is set by the tunnel provider. A netmask is not needed because
it is taken from the variable IPV6_TUNNEL_x_LOCALV6. This information is unnecessary
for tunnel providers assigning new tunnel endpoints for every tunnel established (Such
providers are not yet supported).
Example: IPV6_TUNNEL_1_REMOTEV6='2001:db8:1743::1'
IPV6_TUNNEL_x_DEV (optional) This variable contains the name of the network interface
of the tunnel to be created. Different tunnels have to be named differently to make
everything work. If the variable is not defined a tunnel name is generated automatically
(“v6tun” + tunnel index).
Example: IPV6_TUNNEL_1_DEV='6in4'
IPV6_TUNNEL_x_MTU (optional) This variable contains the size of the MTU (Maximum
Transfer Unit) in bytes, i.e. the the size of the largest packet that can still be tunneled.
This information is generally predetermined by the tunnel provider. If nothing is specified
the standard setting is “1280” and should work with all tunnels.
Default setting: IPV6_TUNNEL_1_MTU='1280'
To prevent a host blocking a tunnel although it does not need it at all some providers require
permanently sending packets over the tunnel to the provider to prove it is still “alive”. For this
purpose a so-called heartbeat protocol is used. Providers usually require a successful login with
user name and password in order to avoid abuse. If such a heartbeat tunnel is used (as offered
by SixXS) then appropriate information has to be passed which will be described below.
IPV6_TUNNEL_x_USERID This variable holds the username needed for the tunnel login.
Example: IPV6_TUNNEL_1_USERID='ABCDE-SIXXS'
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