Technical data

4. Packages
an IPv6 address using STUNNEL_1_ACCEPT='IPV6_NET_2_IPADDR:443' or vice versa by
using (STUNNEL_1_ACCEPT_IPV4='no' and IP_NET_x_IPADDR). Furthermore, the mean-
ing of “any” depends on the Layer 3 protocols activated (IPv4 or IPv6): of course,
the tunnel only listens on addresses belonging to the Layer-3-Protocols activated via
STUNNEL_x_ACCEPT_IPV4 and STUNNEL_x_ACCEPT_IPV6.
STUNNEL_x_ACCEPT_IPV4 This variable controls if the IPv4 protocol is used for incom-
ing connections to the tunnel. Typically this is the case and this variable should be
set to “yes” while “no” ensures that the tunnel only accepts incoming IPv6 connections.
However, this requires a valid IPv6 configuration (refer to the documentation for the ipv6
package for more information).
Default setting: STUNNEL_x_ACCEPT_IPV4='yes'
Example: STUNNEL_1_ACCEPT_IPV4='no'
STUNNEL_x_ACCEPT_IPV6 Like in STUNNEL_x_ACCEPT_IPV4 this variable controls whether
the IPv6 protocol is used for incoming connections to the tunnel. Typically this is the
case if you use the the general IPv6 protocol by using OPT_IPV6='yes'. Setting “no”
here ensures that the tunnel only accepts incoming IPv4 connections.
Default setting: STUNNEL_x_ACCEPT_IPV6=<Values from OPT_IPV6>
Example: STUNNEL_1_ACCEPT_IPV6='no'
STUNNEL_x_CONNECT Sets the target of the SSL/TLS tunnel. There are basically three
possibilities and all must have the port appended, separated by a colon (“:”):
• A numeric IPv4- or IPv6 address
Example 1: STUNNEL_1_CONNECT='192.0.2.2:443'
• The DNS name of an internal host
Example 2: STUNNEL_1_CONNECT='@webserver:443'
• The DNS name of an external host
Example 3: STUNNEL_1_CONNECT='@www.example.com:443'
If an internal host is entered with both IPv4 and IPv6 address, the IPv4 address is
preferred. If an external host is entered with both IPv4 and IPv6 address, then the
Layer 3 protocol used depends on which address is first returned by the DNS resolver.
STUNNEL_x_OUTGOING_IP With this optional variable, the local address for the outgoing
connection of the tunnel can be set. This is only useful if the target of the tunnel can be
reached over multiple interfaces (routes), i.e. if two concurrent Internet connections are
used. Normally, this variable must not be set.
Example: STUNNEL_1_OUTGOING_IP='IP_NET_1_IPADDR'
STUNNEL_x_DELAY_DNS If this optional variable is set to “yes”, an external DNS name
used in STUNNEL_x_CONNECT will not be converted to an address until the outbound tunnel
is established, meaning the point when the first client has connected locally with the
incoming side of the tunnel. This is useful if the target of the tunnel is a computer that
201