StrongSwan as configured on Knoppix 8.1 isn't really useful ...

[hb <hb09@mnet-mail.de>]

or, more or less the same problems as with Knoppix 7.7.1:
- XAuth is not installed and installing it is not straight forward
- The kernel doesn't seem to be configured to support whatever
(allocating SPI) strongSwan needs.

# ipsec --version
Linux strongSwan U5.6.0/K4.12.7-64
Institute for Internet Technologies and Applications
University of Applied Sciences Rapperswil, Switzerland
See 'ipsec --copyright' for copyright information.
#

# ipsec up remote
...
no XAuth method found


# aptitude update
...

# aptitude install libcharon-extra-plugins
The following NEW packages will be installed:
  libcharon-extra-plugins{b} libfcgi-bin{a} libfcgi0ldbl{a}
0 packages upgraded, 3 newly installed, 0 to remove and 1214 not upgraded.
Need to get 490 kB of archives. After unpacking 1,501 kB will be used.
The following packages have unmet dependencies:
 libcharon-extra-plugins : Depends: libstrongswan (= 5.2.1-6+deb8u2) but
5.5.1-3 is installed
The following actions will resolve these dependencies:

     Keep the following packages at their current version:
1)     libcharon-extra-plugins [Not Installed]



Accept this solution? [Y/n/q/?] n
The following actions will resolve these dependencies:

     Downgrade the following packages:

1)     libstrongswan [5.5.1-3 (now, testing, unstable) -> 5.2.1-6+deb8u2
(stable
2)     libstrongswan-standard-plugins [5.5.1-3 (now, testing, unstable)
-> 5.2.1
3)     strongswan-charon [5.5.1-3 (now, testing, unstable) ->
5.2.1-6+deb8u2 (st
4)     strongswan-libcharon [5.5.1-3 (now, testing, unstable) ->
5.2.1-6+deb8u2
5)     strongswan-starter [5.5.1-3 (now, testing, unstable) ->
5.2.1-6+deb8u2 (s



Accept this solution? [Y/n/q/?] q
Abandoning all efforts to resolve these dependencies.
Abort.
#

# aptitude install libcharon-extra-plugins=5.5.1-3
The following NEW packages will be installed:
  libcharon-extra-plugins
0 packages upgraded, 1 newly installed, 0 to remove and 1214 not upgraded.
Need to get 254 kB of archives. After unpacking 849 kB will be used.
Get: 1 http://ftp.de.debian.org/debian testing/main i386
libcharon-extra-plugins i386 5.5.1-3 [254 kB]
Fetched 254 kB in 0s (498 kB/s)
Selecting previously unselected package libcharon-extra-plugins.
(Reading database ... 444301 files and directories currently installed.)
Preparing to unpack .../libcharon-extra-plugins_5.5.1-3_i386.deb ...
Unpacking libcharon-extra-plugins (5.5.1-3) ...
Setting up libcharon-extra-plugins (5.5.1-3) ...

# ipsec restart
Stopping strongSwan IPsec...
Starting strongSwan 5.5.1 IPsec [starter]...

# ipsec up remote
...
XAuth authentication of '<username>' (myself) successful
...
installing DNS server <DNS1_IP> to /etc/resolv.conf
installing DNS server <DNS2_IP> to /etc/resolv.conf
installing new virtual IP <VIRTUAL_IP>
allocating SPI failed: Operation not supported (95)
unable to get SPI
allocating SPI from kernel failed
removing DNS server <DNS2_IP> from /etc/resolv.conf
removing DNS server <DNS1_IP> from /etc/resolv.conf
establishing connection 'remote' failed