<s>
strongSwan	B-Protocol
is	O
a	O
multiplatform	O
IPsec	B-Protocol
implementation	O
.	O
</s>
<s>
The	O
focus	O
of	O
the	O
project	O
is	O
on	O
authentication	O
mechanisms	O
using	O
X.509	O
public	B-Application
key	I-Application
certificates	O
and	O
optional	O
storage	O
of	O
private	B-Application
keys	I-Application
and	O
certificates	O
on	O
smartcards	O
through	O
a	O
PKCS	O
#11	O
interface	O
and	O
on	O
TPM	O
2.0	O
.	O
</s>
<s>
As	O
a	O
descendant	O
of	O
the	O
FreeS/WAN	B-Protocol
project	O
,	O
strongSwan	B-Protocol
continues	O
to	O
be	O
released	O
under	O
the	O
GPL	B-License
license	I-License
.	O
</s>
<s>
It	O
supports	O
certificate	B-Protocol
revocation	I-Protocol
lists	I-Protocol
and	O
the	O
Online	B-Protocol
Certificate	I-Protocol
Status	I-Protocol
Protocol	I-Protocol
(	O
OCSP	B-Protocol
)	O
.	O
</s>
<s>
StrongSwan	B-Protocol
interoperates	O
with	O
other	O
IPsec	B-Protocol
implementations	I-Protocol
,	O
including	O
various	O
Microsoft	B-Application
Windows	I-Application
and	O
macOS	B-Application
VPN	B-Application
clients	I-Application
.	O
</s>
<s>
The	O
current	O
version	O
of	O
strongSwan	B-Protocol
fully	O
implements	O
the	O
Internet	B-Protocol
Key	I-Protocol
Exchange	I-Protocol
(	O
IKEv2	B-Protocol
)	O
protocol	O
defined	O
by	O
RFC	O
7296	O
.	O
</s>
<s>
strongSwan	B-Protocol
supports	O
IKEv1	B-Protocol
and	O
fully	O
implements	O
IKEv2	B-Protocol
.	O
</s>
<s>
strongSwan	B-Protocol
offers	O
plugins	O
,	O
enhancing	O
its	O
functionality	O
.	O
</s>
<s>
The	O
user	O
can	O
choose	O
among	O
three	O
crypto	O
libraries	O
(	O
legacy	O
 [ non-US ] 	O
FreeS/WAN	B-Protocol
,	O
OpenSSL	O
,	O
and	O
gcrypt	O
)	O
.	O
</s>
<s>
Using	O
the	O
openssl	O
plugin	O
,	O
strongSwan	B-Protocol
supports	O
Elliptic	O
Curve	O
Cryptography	O
(	O
ECDH	O
groups	O
and	O
ECDSA	O
certificates	O
and	O
signatures	O
)	O
both	O
for	O
IKEv2	B-Protocol
and	O
IKEv1	B-Protocol
,	O
so	O
that	O
interoperability	O
with	O
Microsoft	O
's	O
Suite	O
B	O
implementation	O
on	O
Vista	O
,	O
Win	O
7	O
,	O
Server	O
2008	O
,	O
etc	O
.	O
</s>
<s>
Automatic	O
assignment	O
of	O
virtual	O
IP	O
addresses	O
to	O
VPN	B-Application
clients	I-Application
from	O
one	O
or	O
several	O
address	O
pools	O
using	O
either	O
the	O
IKEv1	B-Protocol
ModeConfig	O
or	O
IKEv2	B-Protocol
Configuration	O
payload	O
.	O
</s>
<s>
The	O
ipsec	B-Protocol
pool	O
command	O
line	O
utility	O
allows	O
the	O
management	O
of	O
IP	O
address	O
pools	O
and	O
configuration	O
attributes	O
like	O
internal	O
DNS	O
and	O
NBNS	O
servers	O
.	O
</s>
<s>
The	O
IKEv2	B-Protocol
daemon	O
is	O
inherently	O
multi-threaded	O
(	O
16	O
threads	O
by	O
default	O
)	O
.	O
</s>
<s>
The	O
IKEv2	B-Protocol
daemon	O
comes	O
with	O
a	O
High-Availability	O
option	O
based	O
on	O
Cluster	O
IP	O
where	O
currently	O
a	O
cluster	O
of	O
two	O
hosts	O
does	O
active	O
load-sharing	O
and	O
each	O
host	O
can	O
take	O
over	O
the	O
ESP	O
and	O
IKEv2	B-Protocol
states	O
without	O
rekeying	O
if	O
the	O
other	O
host	O
fails	O
.	O
</s>
<s>
EAP-MSCHAPv2	O
authentication	O
based	O
on	O
user	O
passwords	O
and	O
EAP-TLS	O
with	O
user	O
certificates	O
are	O
interoperable	O
with	O
the	O
Windows	O
7	O
Agile	O
VPN	B-Application
Client	I-Application
.	O
</s>
<s>
Support	O
of	O
RFC	O
4739	O
IKEv2	B-Protocol
Multiple	O
Authentication	O
Exchanges	O
.	O
</s>
<s>
Support	O
of	O
RFC	O
5685	O
IKEv2	B-Protocol
Redirection	O
.	O
</s>
<s>
Support	O
of	O
the	O
RFC	O
4555	O
Mobility	O
and	O
Multihoming	O
Protocol	O
(	O
MOBIKE	O
)	O
which	O
allows	O
dynamic	O
changes	O
of	O
the	O
IP	O
address	O
and/or	O
network	O
interface	O
without	O
IKEv2	B-Protocol
rekeying	O
.	O
</s>
<s>
MOBIKE	O
is	O
also	O
supported	O
by	O
the	O
Windows	O
7	O
Agile	O
VPN	B-Application
Client	I-Application
.	O
</s>
<s>
The	O
strongSwan	B-Protocol
IKEv2	B-Protocol
NetworkManager	O
applet	O
supports	O
EAP	O
,	O
X.509	O
certificate	O
and	O
PKCS	O
#11	O
smartcard	O
based	O
authentication	O
.	O
</s>
<s>
A	O
strongSwan	B-Protocol
VPN	B-Application
client	I-Application
can	O
act	O
as	O
a	O
TNC	O
client	O
and	O
a	O
strongSwan	B-Protocol
VPN	B-Application
gateway	O
as	O
a	O
Policy	O
Enforcement	O
Point	O
(	O
PEP	O
)	O
and	O
optionally	O
as	O
a	O
co-located	O
TNC	O
server	O
.	O
</s>
<s>
The	O
IKEv2	B-Protocol
daemon	O
has	O
been	O
fully	O
ported	O
to	O
the	O
Android	B-Application
operating	I-Application
system	I-Application
including	O
integration	O
into	O
the	O
Android	B-Application
VPN	B-Application
applet	O
.	O
</s>
<s>
It	O
has	O
also	O
been	O
ported	O
to	O
the	O
Maemo	B-Operating_System
,	O
FreeBSD	B-Operating_System
and	O
macOS	B-Application
operating	O
systems	O
.	O
</s>
<s>
The	O
focus	O
of	O
the	O
strongSwan	B-Protocol
project	O
lies	O
on	O
strong	O
authentication	O
by	O
means	O
of	O
X.509	O
certificates	O
,	O
as	O
well	O
as	O
the	O
optional	O
safe	O
storage	O
of	O
private	B-Application
keys	I-Application
on	O
smart	O
cards	O
using	O
the	O
standardized	O
PKCS	O
#11	O
interface	O
,	O
strongSwan	B-Protocol
certificate	O
check	O
lists	O
and	O
On-line	O
Certificate	O
Status	O
Protocol	O
(	O
OCSP	B-Protocol
)	O
.	O
</s>
<s>
strongSwan	B-Protocol
comes	O
with	O
a	O
simulation	O
environment	O
based	O
on	O
KVM	B-Application
.	O
</s>
<s>
A	O
network	O
of	O
eight	O
virtual	O
hosts	O
allows	O
the	O
user	O
to	O
enact	O
a	O
multitude	O
of	O
site-to-site	O
and	O
roadwarrior	B-General_Concept
VPN	B-Application
scenarios	O
.	O
</s>
