Libreswan

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Warning.png Warning:
Note that you should try and learn as much as you can about VPN, Ipsec, and Security in general before playing with this. You risk leaving your server exposed to the bad guys.

Whilst the contribs do their best to make sure there is a simple secure setup, I make no guarantees !

Where possible use RSA keys or certificates instead of passwords.

An alternative solution is https://wiki.contribs.org/OpenVPN_SiteToSite or https://wiki.contribs.org/OpenVPN_Bridge

Where possible avoid the use of PPTP as it was cracked a long time ago and is very easy to read


Version

Koozali SME v8

Centos 5:
openswan
Please use the version of openswan in the ReetP repo as below
smeserver-openswan
The latest version of smeserver-openswan is available in the SME repository, click on the version number(s) for more information.


Koozali SME v9

Devel 9:
libreswan
The latest version of libreswan is available in the SME repository, click on the version number(s) for more information.
Contrib 9:
smeserver-libreswan
The latest version of smeserver-libreswan is available in the SME repository, click on the version number(s) for more information.


About

Openswan

Openswan.jpg

Openswan is a free implementation of IPsec & IKE for Linux. IPsec is the Internet Protocol Security and uses strong cryptography to provide both authentication and encryption services. These services allow you to build secure tunnels through untrusted networks. Everything passing through the untrusted net is encrypted by the ipsec gateway machine and decrypted by the gateway at the other end of the tunnel.The resulting tunnel is a virtual private network or VPN.

Libreswan

Libreswan is a free software implementation of the most widely supported and standarized VPN protocol based on ("IPsec") and the Internet Key Exchange ("IKE"). These standards are produced and maintained by the Internet Engineering Task Force ("IETF").

Note that Libreswan will become the default ipsec installation from CentOS 6.8

https://libreswan.org/wiki/HOWTO:_openswan_to_libreswan_migration

  • Credits: John Crisp
  • Discuss: This How-to can be discussed on the forums here


Installation

[edit]

For Koozali SME Server 8 you will need the ReetP repo to install openswan

db yum_repositories set reetp repository \
BaseURL https://reetspetit.com/smeserver/\$releasever \
EnableGroups no GPGCheck no \
Name "Mirror John Crisp reetspetit.com" \
GPGKey https://reetspetit.com/RPM-GPG-KEY \
Visible yes status disabled



signal-event yum-modify

Note that the contrib is currently in test so to install:

yum --enablerepo=smetest,reetp install smeserver-openswan

Configuration options and notes are here (check the latest branch):

https://github.com/reetp/smeserver-openswan

Please note that this version is no longer under development as SME v8 is EOL at the end of March 2017

It is possible to use Openswan on SME v9 but I do not have the time to maintain the contrib for both versions. RedHat have swapped to using Libreswan as their default IPsec implementation.

For Koozali SME Server 9, the latest stable Libreswan can be found in the default repo's

Note that the contrib is currently in test so to install:

yum --enablerepo=smetest install smeserver-libreswan

Configuration options and notes are here (check the latest branch):

https://github.com/reetp/smeserver-libreswan


Important.png Note:
You can get the latest version of libreswan itself here

/sbin/e-smith/db yum_repositories set libreswan repository \
BaseURL https://download.libreswan.org/binaries/rhel/6/x86_64/ \
EnableGroups no \
GPGCheck yes \
GPGKey https://download.libreswan.org/binaries/RPM-GPG-KEY-libreswan \
Name LibreSwan \
Visible yes \
status disabled \
signal-event yum-modify
yum --enablerepo=libreswan install libreswan


IPSEC server to server configuration

Libreswan/Openswan/IPSEC can be used to setup a secure and permanent VPN connection between a SME Server and another (local or remote) IPSEC enabled device such as a router.

Note - if you want to use with an online VPS set the server to server/gateway with a 'dummy' internal network adaptor.

Passwords

It is recommended to create a very strong random password and keep this safe. One way of generating and store a random strong password is explained here

Alternatively see RSA key and Certificate sections below for much stronger passwords


Setup PSK Passwords

The contrib has a lot of configurable settings but with the defaults and a few details it should just work.

General settings and some defaults are stored in the main config DB

config show ipsec

Connection specific settings are stored in a separate DB

db ipsec_connections show


Important.png Note:
For ipsec_connections we use 'set' when we create a new connection. Thereafter you can modify it with setprop


Important.png Note:
Most people refer to East and West rather than Local and Remote. There is a very good reason for this if you start using RSA keys !

Server East - WAN IP 5.6.7.8 Local IP 192.168.20.1 Subnet 192.168.20.0/24

db ipsec_connections set MyEast ipsec status enabled leftsourceip 192.168.20.1 leftsubnet 192.168.20.0/24 right 1.2.3.4 rightsubnet 10.0.0.0/24 passwd MyPassWd

Server West- WAN IP 1.2.3.4 Local IP 10.0.0.1 Subnet 10.0.0.0/24

db ipsec_connections set MyWest ipsec status enabled leftsourceip 10.0.0.1 leftsubnet 10.0.0.0/24 right 5.6.7.8 rightsubnet 192.168.20.0/24 passwd MyPassWd
signal-event ipsec-update


Setup RSA Keys

For the better security it is recommended to use RSA keys.

There are notes on github as this can be quite lengthy

https://github.com/reetp/smeserver-libreswan/blob/master/IpsecSettings.txt

A basic ipsec_connections entry setup should look this - note it will need a matching setup at the other end):

MyEast=ipsec 
   leftsourceip=192.168.20.1
   leftsubnet=192.168.20.0/24
   right=1.2.3.4
   rightsubnet=10.0.0.0/24
   security=rsasig
   leftid=East
   rightid=West
   leftrsasig=SomeLongPassFromEast
   rightrsasig=SomeLongPasswordFromWest
   status enabled


Setup Certificates

You can now use a CA and PKCS#12 certificates.

There are notes on github as this can be quite lengthy

https://github.com/reetp/smeserver-libreswan/blob/master/ipsec-certificate-notes.txt

A basic ipsec_connections entry setup should look this:

MyEast=ipsec
   leftcert=LocalServer
   leftsourceip=192.168.1.1
   leftsubnet=192.168.1.0/24
   right=5.6.7.8
   rightcert=RemoteServer
   rightsubnet=192.168.100.0/24
   security=certs
   status=enabled


DB Keys

There are a lot of keys involved in ipsec.

Where possible just use the minimum that you require depending on whether you want PSK password / RSA signature / Certificate security

There are notes on github as this can be quite lengthy

https://github.com/reetp/smeserver-libreswan/blob/master/IpsecSettings.txt

Here are the currently available settings and options:


IPsec settings

These settings are generic and can be overwritten on a per connection basis

config ipsec show

Only set with: db configuration setprop ipsec $key $property

Setting status enabled/disabled will modify access to private/public

status: Default disabled | enabled
access: Default private | public
UDPPorts: Default 500,4500 | Variable
auto: Default start | add (do not use ondemand or ignore)
debug: none | all raw crypt parsing emitting control controlmore lifecycle dns dpd klips pfkey natt oppo oppoinfo whackwatch private

(all generates a LARGE amount of logging so use with care)


General Settings

Overall default settings - these can be in main config db or set per connection in db ipsec_connections

security: secret | rsasig | certs
ikelifetime: Default 3600s | Variable
salifetime: Default 28800s | Variable
dpdaction: Default restart | Variable
dpddelay: Default 30 | Variable
dpdtimeout: Default 10 | Variable
pfs: Default yes | Variable
connectiontype: Default secret | rassig, certificate
ike: Default aes-sha1 | Variable - see ipsec.conf readme file for more options - sample: aes256-sha2;dh14 or aes256-sha2;modp2048
ipsecversion: Default permit | Whether to allow ikev2 - also : insist/propose/yes/never/no

Per connection settings

Warning.png Warning:
Automatically modified - do not change this

PreviousState: Denotes previous connection state


Manual keys

db ipsec_connections show
db ipsec_connections setprop ConnectionName $key $property
iptype: Default Empty | stattodyn or dyntostat - are we a static host to dynamic client or vice versa ? - Only required for dynamic clients with static hosts
connectiontype: Default tunnel | transport/passthrough/drop/reject
leftrsasig: Default Empty | Your Local rsasignature key
rightrsasig: Default Empty | Your Remote rsasignature key
ipsecversion: Default permit | Whether to allow ikev2 - also : insist/propose/yes/never/no 
ike: Default aes-sha1 | Variable - sample: aes256-sha2;dh14 or aes256-sha2;modp2048
phase2: Default aes-sha1 | Variable - sample: aes256-sha2;dh14 or aes256-sha2;modp2048
mtu: Default Empty | Variable
left: Default Empty | If Empty then %defaultroute is set. Can be local WAN IP
leftid: Default Empty | Variable
leftsourceip:  Default Empty | This server local IP
leftsubnet:  Default Empty | This server local subnet
right: Default Empty | Destination WAN IP
rightid: Default Empty | Variable
rightsubnet: Default Empty | Destination subnet
passwd: Default Empty | Variable
keyingtries: Default Empty | 0 is default - 'forever'
leftcert Default Empty | LeftCertName
rightcert Default Empty | RightCertName

For certificates - do not set or leave the following empty:

leftrsasig: Default Empty - system generates %cert
rightrsasig: Default Empty - system generates %cert
leftid: Default Empty - system generates %fromcert
rightid: Default Empty - system generates %fromcert

Logs and Debug

Warning.png Warning:
If you are trying to connect Libreswan to other *swan versions using IPsec v2 you may see this in the logs
"failed to match authenticator"

which may cause link failures. This seems to be an issue with some *swan versions - see this thread for more https://lists.libreswan.org/pipermail/swan/2017/001956.html


The following will give you connection details.

ipsec whack --status

You should get this if the connection made : 'IPsec SA established'

The following check your configuration (may be some warnings - severity depends on what they are):

ipsec verify 

If you modify a connection use

signal-event ipsec-update

For a restart of ipsec use

service ipsec restart

You may find masq needs a restart sometimes

/etc/init.d/masq restart

Check /var/log/iptables/current to see if packets are getting blocked.

For ipsec itself place to look is /var/log/pluto/pluto.log

If you need more debugging you can set plutodebug = all


Bug report

SME8 OpenSwan IPSEC is listed in the bugtracker contribs section. Please report all bugs, new feature requests and documentation issues there.

"No open bugs found."

SME9 LibreSwan IPSEC is listed in the bugtracker contribs section. Please report all bugs, new feature requests and documentation issues there.

IDProductVersionStatusSummary
10661SME Contribs9.2CONFIRMEDNew file to adjust redirects in /etc/sysctl.d

Other articles in this category

Ipsec, Libreswan, Libreswan IPSEC, OpenVPN, OpenVPN Bridge, OpenVPN Routed, OpenVPN SiteToSite, SME Server wishlist, Smeserver-libreswan-xl2tpd, SoftEther VPN, VPN